Solve for y. Note the equal sign. What you do to one side, you do to the other. Isolate the y. Do the opposite of PEMDAS.
First, subtract x from both sides
y²z + x (-x) = b (-x)
y²z = b - x
Next, divide z from both sides
(y²z)/z = (b - x)/z
y² = (b - x)/z
Finally, to fully isolate the x, root both sides
√(y²) = √((b - x)/z)
y = √((b - x)/z)
y = √((b - x)/z) is your answer
hope this helps