Question

Solve using substitution x+y+2z=-7 / -5z=25 / 3x-3y-6z=3

Answer 1

x = -3

y = 6

z = -5

Explanation:

A) x + y + 2z = -7

B) -5z = 25

C) 3x - 3y - 6z = 3

B) -5z = 25

z = 25/-5

(z = -5)

A) x + y + 2(-5) = -7

x + y = -7 + 10

x + y = 3

(x = 3 - y)

C) 3x - 3y + 6(-5) = 3

3x - 3y + 30 = 3

3x - 3y = -30-3

3x - 3y = - 27

C) 3 (3-y) - 3y + 30 = 3

9 - 3y - 3y+ 30 = 3

-6y + 39 = 3

-6y = -39 + 3

y = -36/-6

(y = 6)

x + 6 = 3

x = 3 -6

(x = -3)