Solve x^2+20=400

$$x ^ { 2 } + 20 = 400$$

Solve for x

$$x=2\sqrt{95}\approx 19.49358869$$

$$x=-2\sqrt{95}\approx -19.49358869$$

Steps by Finding Square Root

Subtract 20 from both sides.

$$x^{2}=400-20$$

Subtract 20 from 400 to get 380.

$$x^{2}=380$$

Take the square root of both sides of the equation.

$$x=2\sqrt{95} x=-2\sqrt{95}$$

Steps Using the Quadratic Formula

Subtract 400 from both sides.

$$x^{2}+20-400=0$$

Subtract 400 from 20 to get -380.

$$x^{2}-380=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -380 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\left(-380\right)}}{2}$$

Square 0.

$$x=\frac{0±\sqrt{-4\left(-380\right)}}{2}$$

Multiply -4 times -380.

$$x=\frac{0±\sqrt{1520}}{2}$$

Take the square root of 1520.

$$x=\frac{0±4\sqrt{95}}{2}$$

Now solve the equation x=\frac{0±4\sqrt{95}}{2} when ± is plus.

$$x=2\sqrt{95}$$

Now solve the equation x=\frac{0±4\sqrt{95}}{2} when ± is minus.

$$x=-2\sqrt{95}$$

The equation is now solved.

$$x=2\sqrt{95} x=-2\sqrt{95}$$