Given that R
=
2
x
+
9
y

Find
x
when
y
=
3
and
R
=
13
.

-7

Step-by-step explanation:

To find x, substitute the values and solve.

R = 2x + 9y

It becomes:

2x  + 27 = 13

Rearrange and solve

2x = -14

x = -7

Hope this helps

x=-7

Step-by-step explanation:

We are given the expression:

R=2x +9y

We want to find x when R=13 and y=3. Therefore, we must substitute the numbers in for the variables.

13=2x+9(3)

Multiply 9 and 3.

13=2x+27

Now we must solve for x by isolating x on one side of the equation.

27 is being added to 2x. The inverse of addition is subtraction, so subtract 27 from both sides.

13-27=2x+27-27

13-27=2x

-14=2x

x is being multiplied by 2. The inverse of multiplication is division, so divide both sides by 2.

-14/2=2x/2

-14/2=x

-7=x

x=-7

we know it's a perfect square so the first term has to be 4x and the second 3. let's check:

so the length of each side is

part b

that's the difference of two squares:

at this point we're supposed to say the rectangle's dimensions are

2x-7y by 2x+7y

but that's horse hockey. the rectangle dimensions are l, any positive number, and

but i'm almost certain they're expecting the wrong answer:

2x-7y by 2x+7y