Which equations are true equations?

Select all correct answers.

150/5^2=30−4^2−12

8⋅7/2−12=22−2⋅3

48 ÷ 8 + 2³ = 5 + 3²

9^2−7^2=20÷(7−2)

9514 1404 393

Answer:

  (x, y) = (1.25, 8.5)

Step-by-step explanation:

I choose to put these equations into reduced general form, then use the "cross multiplication method" to solve.

  2x -y +6 = 0

  10x -y -4 = 0

d1 = 2(-1) -10(-1) = 8

d2 = -1(-4) -(-1)(6) = 10

d3 = 6(10) -(-4)(2) = 68

Solutions are ...

  x = d2/d1 = 10/8 = 1.25

  y = d3/d1 = 68/8 = 8.5

The solution is (x, y) = (1.25, 8.5).

_____

Additional comment

I like a graphing calculator for a quick and easy solution. When the values are not integers, I like an algebraic solution to see what the exact values are.

__

The "cross multiplication method" is similar to Cramer's rule in that determinants of pairs of coefficients are computed. If you look up this method, videos will show you a variation that is slightly different. Here, we determined d1, d2, and d3 as the 2×2 determinant of the coefficients in adjacent columns of the array you get from the general form equations with the first column repeated:

  [tex]\begin{array}{cccc}2&-1&6&2\\10&-1&-4&10\end{array}[/tex]

In each pair, the determinant is the difference between the product of numbers on the down-diagonal and the product of numbers on the up-diagonal.

The determinants relate to the x- and y-values by ...

  1/d1 = x/d2 = y/d3   ⇒   x = d2/d1, y = d3/d1

There is a Vedic solution method for linear equations that is similar to this, but starts from equations in standard form. As a consequence, the cross-differences are done in a different order.

__

Standard form: ax +by = c

General form: ax +by +c = 0

9514 1404 393

Answer:

  C)  ΔDCE ≅ ΔDQR

Step-by-step explanation:

Corresponding vertices can be identified by the number of arcs signifying congruence.

  1 mark: angles D and D

  2 marks: angles C and Q

  3 marks: angles E and R

Corresponding angles are listed in the same order in the congruence statement:

  ΔDCE ≅ ΔDQR

Answer:

They are equal, so =

Step-by-step explanation:

We know that one-half is .50.  3/2 is an improper fraction and when we solve to a decimal, we get 1.5.  

9514 1404 393

Answer:

  B.  2/3

Step-by-step explanation:

The slope is given by the formula ...

  m = (y2 -y1)/(x2 -x1)

For points (x1, y1) = (-3, -7) and (x2, y2) = (9, 1), the slope is ...

  m = (1 -(-7))/(9 -(-3)) = 8/12 = 2/3

The slope of the line is 2/3.

Step-by-step explanation:

Infinity means that it has no end to something

And undefined means something can't be defined

Answer:

Undefined means, it is impossible to solve.

Infinity means, it is without bound.

Answer:

$10.4

Step-by-step explanation:

mark me brainliest if u are kind

Usually a company may charge a startup fee, is a charge for some things they need to do to start the service, in this case may just be paperwork, and it's $19.95, a fixed cost, and they're charging 17 cents or $0.17 for every mile driven, let's say that Molly is going to drive "m" miles, so the cost equation in "m" terms will be C(m) = 19.95 + 0.17m.

Now, we know she only has 40 bucks to spend, so, if she can keep her Cost to 40 bucks, how many miles can she go for?

[tex]C(m) = 19.95+0.17m\qquad \qquad \stackrel{\stackrel{cost}{\downarrow }}{40}=19.95+0.17m\implies 20.05=0.17m \\\\\\ \cfrac{20.05}{0.17}=m\implies 117.94\approx m[/tex]

now, if we were to round that up to whole miles, it'd be only 117.

Answer:

=

6

=

0

Step-by-step explanation:

The solution to the quadratic equation (x - 2)(x - 4) = 8 are 0 and 6.

A quadratic equation is an algebraic expression in the form of variables and constants.

A quadratic equation has two roots as its degree is two.

Given, A quadratic equation (x - 2)(x - 4) = 8.

∴ x² - 4x - 2x + 8 = 8.

x² - 6x = 0.

x(x - 6) = 0.

So, x = 0 Or x - 6 = 0 ⇒ x = 6.

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Answer:

3.49 ft

Step-by-step explanation:

y = 0.125x

y = –16x^2 + 56x

Set the equations equal since the height of the hill

and the height of the ball must be the same

–16x^2 + 56x = 0.125x

Subtract 0.125x from both sides

–16x^2 + 55.875x = 0

Factor out x

x(–16x + 55.875) = 0

From the zero product rule

x = 0

and

–16x + 55.875 = 0

–16x = –55.875

Divide both sides by –16

x = 3.4921875

Diiference in height

3.4921875 - 0 = 3.4921875

3.49 ft

Answer:

Jon’s, because he will have a higher quality of life

Step-by-step explanation:

James wants to live in a cheap living condition so his quility is going to be worse. John wants to live in a posh urban setting and posh urban is higher quility than cheap living condition. So the anwser is C.

Answer:

Step-by-step explanation:

James

Answer:

6720.

1680.

Step-by-step explanation:

There are 3 T's and 5 other distinct letters in this word s

The number of arrangements

= 8! / 3!

= 8*7*6*5*4

= 6720 ways.

If N and G are next to each other  we consider it to be 1 letter. Now we can have GN or NG so the answer is

(7!/3!) * 2

= 1680 ways.

Answer:

The answer is 31

Explanation:

25 - (-6) = 31

we have 25 - (-6) = 25 + 6 = 31

so the answer is D

ok done. thank to me :>

Answer: C.

Step-by-step explanation:

Total number of plants in Robert's garden = 8 + 4 + 16 + 22

= 50

Number of tomato plants in Robert's garden = 8

Ratio of total number of plants to the number of tomato plants = 50 : 8

Simplify

50 : 8 = 25:4

Answer:

exposed by making a straight cut through a solid form, especially at right angles to an axis.

"the cross-sectional area of the wood"

or

constituting a typical or representative sample of a larger group.

"a cross-sectional survey of high school students"

ig

Answer:

[tex]\frac{12}{23} + (9 \frac{6}{8} - 3 \frac{1}{4})[/tex]

Exact Form:

[tex]\frac{323}{46}[/tex]

Decimal Form:

7.02173913  

Mixed Number Form:

7 [tex]\frac{1}{46}[/tex]

Step-by-step explanation:

The linear function that can be used to model this relationship is:

y = -0.27x + 23

A linear function is in the form:

y = mx + b

where y, x are variables, m is the rate of change and b is the initial value of y.

Let P(x) represent the percentage of total  spending x years after 1950.

Since In 1950, the group spent 23% of their budget on food, hence b = 23.

Also, this has been decreasing at 0.27% per year. Hence m = -0.27.

The linear function that can be used to model this relationship is:

y = -0.27x + 23

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Answer:

d =  y = 4.25x

correct answer i would say.

Step-by-step explanation:

Cheddar cheese cost 4.25 per pound . This means the cost of cheddar cheese is 4.25 for every pound in weight. Assuming we put a currency to the value we can say 1 pound of cheddar cheese is equals to 4.25 dollars($4.25). Mathematically, it can be represented as  

4.25 is the cost for 1 pound of Cheddar cheese

Let the cost of the equation be y as required from the question.

y = cost of the cheddar cheese

x is the weight value in pounds of the Cheddar cheese.

The equation can be best represented as

y = 4.25x

In the equation above if the amount in pounds is 3 pound . the value will be inputted for x and the cost will be gotten which is y.

hope this helped!

mark me brainliest :D

Answer:

23

Step-by-step explanation:

l

l

l

l

ll

ll

l

l

l

[tex]\qquad \textit{Heron's area formula} \\\\ A=\sqrt{s(s-a)(s-b)(s-c)}\qquad \begin{cases} s=\frac{a+b+c}{2}\\[-0.5em] \hrulefill\\ a=7.2\\ b=6.7\\ c=4.5\\ s=\frac{7.2+6.7+4.5}{2}\\[0.5em] \qquad 9.2 \end{cases} \\\\\\ A\sqrt{9.2(9.2-7.2)(9.2-6.7)(9.2-4.5)}\implies A=\sqrt{9.2(2)(2.5)(4.7)} \\\\[-0.35em] ~\dotfill\\\\ ~\hfill A\approx 14.704~\hfill[/tex]

Answer:

The answer is C. 14.704

Step-by-step explanation: I just took the test

Answer:

a - 145

b - 35

c - 145

d - 70

e - 70

f - 110

g - 55

h - 125

i - 55

j - 50

k - 50

l - 130

m - 50

n - 80

o - 50

p - 23

q - 89

r - 68

s - 157

t - 112

u - 48

v - 132

w - 132

x - 48

y - 48

z - 132

A - 48

B - 94

C - 86

D - 94

E - 47

F - 133

answer:

1

Step-by-step explanation:

#'s between zero and two = one

the only number between 0 and two is 1

x = 1  y = 1  z = 1

the average value of the sum of the squares of x, y and z = 1

1, 1, 1

the average is 1

Answer:

Step-by-step explanation:

A math class with 12 boys and 16 girls, A science class with 15 boys and 20 girls and A band class with 75 boys and 100 girls have an equivalent ratio of 3 : 4.

Ratio is a concept in mathematics used to compare two things.

It is denoted by a : b.

A ratio can be represented as fractions also like a/b.

In the question, it is given that the ratio of boys to girls is 3 to 4.

Hence A math class with 12 boys and 16 girls, A science class with 15 boys and 20 girls and A band class with 75 boys and 100 girls have an equivalent ratio of 3 : 4.

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Answer:

Which grade math is this? I haven't learned it

well, keeping in mind that to draw a line all we need is two points, now, the one drawn already has many points let's pick two off of it, hmmm (-1,4) and (-6,-2).

Now, let's recall that for inverse functions, the domain of the original is the range of the inverse and the range of the original is the domain of the inverse, what does that mean? heheh, well, it simple means that for any point on the original that is say (a , b), the inverse will have a point at the flipped version of it of (b , a).  So if the orginal has the points aforementioned above, then the inverse will surely have the points of (4 , -1) and (-2 , -6), and we can just draw a line through those.  Check the picture below.

The coefficient of s/3 is 1/3.

s/3 = (1/3)s

No, 3 is not the coefficient of s/3.

An expression is a way of writing a statement with more than two variables or numbers with operations such as addition, subtraction, multiplication, and division.

Example: 2 + 3x + 4y = 7 is an expression.

We have,

s/3

This can be written as (1/3)s.

The coefficients of an equation are the non-zero values along with the variables.

Example:

ax² + bx + 3

The coefficients of this equation are a, and b.

The coefficient for the expression s/3  is 1/3.

Thus,

The coefficient of s/3 is 1/3.

s/3 = (1/3)s

No, 3 is not the coefficient of s/3.

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what is that? Or I am not understanding

Answer:

y = x

Step-by-step explanation:

The equation of a line passing through the origin is

y = mx ( m is the slope )

Calculate m using the slope formula

m = [tex]\frac{y_{2}-y_{1} }{x_{2}-x_{1} }[/tex]

with (x₁, y₁ ) = (0, 0) and (x₂, y₂ ) = (1, 1) ← 2 points on the line

m = [tex]\frac{1-0}{1-0}[/tex] = [tex]\frac{1}{1}[/tex] = 1 , then

y = x ← equation of line

Answer:

Step-by-step explanation:

A. Zero Slope: since it is horizontal

B. Positive Slope: since it goes up and to the right

C. Undefined Slope: since it is vertical

D. Negative Slope: since it goes down and to the left