Solve y=a-x^2

$$y = a - x ^ { 2 }$$

Solve for a

$$a=x^{2}+y$$

Solution Steps

Swap sides so that all variable terms are on the left hand side.

$$a-x^{2}=y$$

Add x^{2} to both sides.

$$a=y+x^{2}$$

Solve for x (complex solution)

$$x=-\sqrt{a-y}$$

$$x=\sqrt{a-y}$$

Solve for x

$$x=\sqrt{a-y}$$

$$x=-\sqrt{a-y}\text{, }y\leq a$$