Solve 90x^2=64800

$$90 x ^ { 2 } = 64800$$

Solve for x

$$x=12\sqrt{5}\approx 26.83281573$$

$$x=-12\sqrt{5}\approx -26.83281573$$

Steps by Finding Square Root

Divide both sides by 90.

$$x^{2}=\frac{64800}{90}$$

Divide 64800 by 90 to get 720.

$$x^{2}=720$$

Take the square root of both sides of the equation.

$$x=12\sqrt{5} x=-12\sqrt{5}$$

Steps Using the Quadratic Formula

Divide both sides by 90.

$$x^{2}=\frac{64800}{90}$$

Divide 64800 by 90 to get 720.

$$x^{2}=720$$

Subtract 720 from both sides.

$$x^{2}-720=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, 0 for b, and -720 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\left(-720\right)}}{2}$$

Square 0.

$$x=\frac{0±\sqrt{-4\left(-720\right)}}{2}$$

Multiply -4 times -720.

$$x=\frac{0±\sqrt{2880}}{2}$$

Take the square root of 2880.

$$x=\frac{0±24\sqrt{5}}{2}$$

Now solve the equation x=\frac{0±24\sqrt{5}}{2} when ± is plus.

$$x=12\sqrt{5}$$

Now solve the equation x=\frac{0±24\sqrt{5}}{2} when ± is minus.

$$x=-12\sqrt{5}$$

The equation is now solved.

$$x=12\sqrt{5} x=-12\sqrt{5}$$