Question

To solve the system of equations below, Maria isolated the variable y in the first equation and then substituted it into the second equation. What was the resulting equation?

{ 3y=12x
{x^2+y=18

A. x^2 + x = 18
B. x^2 − 4x = 18
C. x^2 + 4 = 18
D. x^2 + 4x = 18

Answer 1

y = 4x
The answer is D

Answer 2

D.
`x^2 + 4x = 18`

Explanation:

To solve the system of equations below, Maria isolated the variable y in the first equation and then substituted it into the second equation.

First equation is
`3y=12x`

To isolate y we divide both sides by 3

`y=4x`

Now substitute 4x for y in second equation

`x^2+y=18`

`x^2+4x=18`

this equation is in option D