Question

Use the substitution to solve the system of equations

y= -2x

x-3y=21

Answer 1

y= -2x
x-3y=21

x - 3(-2x) = 21
x + 6x = 21
7x = 21
x = 21/7
x = 3

y= -2x
y = -2*3
y = -6

(3, -6)