Question 39536
(1) 3w - 2z = 38
(2) z = 2w -18
subtract 2w from both sides of (2)
z -2w = -18
rearrange the left side
-2w + z = -18
now we have
(1)  3w - 2z = 38
(2) -2w + z = -18
multiply both sides of (2) by 2
(1)  3w - 2z = 38
(2) -4w + 2z = -36
add (1) to (2)
 -w = 2
multiply both sides by -1
 w = -2
substitute w = -2 in (2)
z = 2*(-2) -18
z = -4 -18
z = -22
check by substituting w and z in (1)
3*(-2) - 2*(-22) = 38
-6 + 44 = 38
38 = 38
OK