Question

3x+y-2z=22 x+5y+z=4 x=-3z

Answer 1

x = 6 ; y = 0 ; z = -2

3x  +   y  - 2z = 22   ⇒  3(6) + 0 -2(-2) = 22 ⇒ 18 + 4 = 22 ⇒ 22 = 22
  x  + 5y  + z =  4     ⇒   6 + 5(0) + (-2) = 4  ⇒  6 - 2 = 4 ⇒ 4 = 4
  x = -3z

3(-3z) + y - 2z = 22
-9z + y - 2z = 22
y - 11z = 22
y = 22 + 11z

x + 5y + z = 4
-3z + 5(22 + 11z) + z = 4
-2z + 110 + 55z = 4
53z = 4 - 110
53z = -106
z = -106/53
z = -2

x = -3(z)
x = -3(-2)
x = 6

y = 22 + 11z
y = 22 + 11(-2)
y = 22 - 22
y = 0