Question

Solve the system of equations by elimination. 2x-y+3z=-1, x+2y-4z=-1, y-2z=0

Answer 1

16, 3x-y=4

3x-3x-y=4-3x

-y=4-3x(multiply both sides by -1 to get...)

y=3x-4

17. -4x-5y=20

-4x+4x-5y=20+4x

5y=4x+20
5y/5=4/5x+20/5
y=4/5x+4

19,
-3x+7(0)=-21
-3x=-21
-3x/-3=-21/-3
x=7