Help with my summer Calculus Packet?

Question

Solve For Z:

y^2 +3yz -8z -4x = 0

Answer 1

2y + 3 = 0

2y= -3

y = -1 1/2

Answer 2

y^2 + 3yz - 8z - 4x = 0

3yz - 8z = 4x - y^2

z (3y - 8) = 4x - y^2

z = (4x - y^2) / (3y - 8)

Answer 3

Take out z common from 2nd and 3rd term, it will become,

y ^ 2 + z(3y - 8z) = 4x

Now to evaluate z, it will come out in terms of x and y,

z = (4x - y ^ 2) / (3y - 8)