Solve x^2+20x+a=0

$$x ^ { 2 } + 20 x + a = 0$$

Solve for a

$$a=-x\left(x+20\right)$$

Solution Steps

Subtract x^{2} from both sides. Anything subtracted from zero gives its negation.

$$20x+a=-x^{2}$$

Subtract 20x from both sides.

$$a=-x^{2}-20x$$

Solve for x (complex solution)

$$x=\sqrt{100-a}-10$$

$$x=-\sqrt{100-a}-10$$

Solve for x

$$x=\sqrt{100-a}-10$$

$$x=-\sqrt{100-a}-10\text{, }a\leq 100$$