Question

Solve the system by substitution.
2x-y+z=-4
z=5
-2x+3y-z=-10

Answer 1

x=-8
y=-7

Answer 2

put z = 5 into equations 1 and 3

2x - y + 5 = -4 or 2x - y = -9 equation 1

-2x + 3y - 5 = -10 -2x + 3y = - 5 equation 2

rewrite equation 1

2x = y - 9

substitute it into equation 2

-(y - 9) + 3y = -5


solve for y...