Please help me with this solving systems of equations algebraically problem if you can or want to

okk from first equation
z = -9 + y
then use that to replace rest of z
y- 5(-9+ y) = 29
y + 45 - 5y = 29
-4y + 45 = 29
-4y = -45 + 29
-4y = -16
-4y/4 = -16/4
y = 4

then replace y in first eq to find z
-4 + z = -9
z = -9 +4
z = -5

Photomath app

Gauss-Jordan again