Answer:
x = 6, y = - 2, z = 4
Explanation:
Substitution:
A) x - 3y + 2(4) = 20
x - 3y +8 = 20
x - 3y = 20-8
x - 3y = 12
B) x - 2y - 4 = 6
x -2y = 6 + 4
x - 2y = 10
A) -1(x - 3y = 12) = -x + 3y = 12
(-x + 3y = -12) + (x - 2y = 10)
= y = -2
B) x - 2(-2) = 10
x +4 = 10
x = 10-4
x = 6