Solve the equation: sqrt z = -1
(sqrt z)^2 = -1^2
Solve the equation: sqrt 2a = 2
(sqrt 2a)^2 = 2^2
2a = 4 Just complete the solution by dividing both sides by 2.
When one side of an eq is a SQRT, squaring both sides is the way to solve.
You're doing great.