Question

solve by substitution:9x + 3y = -30-5x = y

Answer 1

9x + 3y = -30 (a)

-5x = y (b)

Replace the value of y (b) on (a) and solve for x:

9x + 3 (-5x) = -30

9x - 15 x = -30

-6x = -30

x = -30 /-6

x = 5

Replace x = -5 on (b) and solve for y:

-5 (5) = y

-25 = y

Solution:

x = 5

y= -25