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

Respuesta :

y = 4x
The answer is D

Answer:

D. [tex]x^2 + 4x = 18[/tex]

Step-by-step 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 [tex]3y=12x[/tex]

To isolate y we divide both sides by 3

[tex]y=4x[/tex]

Now substitute 4x for y in second equation

[tex]x^2+y=18[/tex]

[tex]x^2+4x=18[/tex]

this equation is in option D