Question

If y=-3x
X+y=9
Solving systems of equations by substitution

Answer 1

x=-4.5 y=13.5

Explanation:

plug in y=-3x to x+y=9

x+(-3x)=9

distribute

x-3x=9

combine like terms

-2x=9

isolate the variable

-2x/-2=9/-2

x=-4.5

plug in x=4.5 into y=-3x

y=-3(-4.5)

simplify

y=-13.5

done :D