Question

Y = 3x + 15 3x + 3y = 9

Answer 1

Answer:

$\Large\boxed{x=-3}$$\Large\boxed{y=6}$

Step-by-step explanation:

Given the system of equations

$1)~y=3x+15$

$2)~3x+3y=9$

Divide 3 on both sides of the 2) equation

$3x+3y=9$

$3x\div3+3y\div3=9\div3$

$x+y=3$

Current system

$1)~y=3x+15$

$2)~x+y=3$

Substitute 1) equation into the 2) equation

$x+(3x+15)=3$

Combine like terms

$x+3x+15=3$

$4x+15=3$

Subtract 15 on both sides

$4x+15-15=3-15$

$4x=-12$

Divide 4 on both sides

$4x\div4=-12\div4$

$\Large\boxed{x=-3}$

Substitute the x value into one of the equations to find the y value

$y=3x+15$

$y=3(-3)+15$

$y=-9+15$

$\Large\boxed{y=6}$

Hope this helps!! :)

Please let me know if you have any questions