Solve 15x*x=300

$$15 x \times x = 300$$

Solve for x

$$x=2\sqrt{5}\approx 4.472135955$$

$$x=-2\sqrt{5}\approx -4.472135955$$

Steps by Finding Square Root

Multiply x and x to get x^{2}.

$$15x^{2}=300$$

Divide both sides by 15.

$$x^{2}=\frac{300}{15}$$

Divide 300 by 15 to get 20.

$$x^{2}=20$$

Take the square root of both sides of the equation.

$$x=2\sqrt{5} x=-2\sqrt{5}$$

Steps Using the Quadratic Formula

Multiply x and x to get x^{2}.

$$15x^{2}=300$$

Subtract 300 from both sides.

$$15x^{2}-300=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 15 for a, 0 for b, and -300 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 15\left(-300\right)}}{2\times 15}$$

Square 0.

$$x=\frac{0±\sqrt{-4\times 15\left(-300\right)}}{2\times 15}$$

Multiply -4 times 15.

$$x=\frac{0±\sqrt{-60\left(-300\right)}}{2\times 15}$$

Multiply -60 times -300.

$$x=\frac{0±\sqrt{18000}}{2\times 15}$$

Take the square root of 18000.

$$x=\frac{0±60\sqrt{5}}{2\times 15}$$

Multiply 2 times 15.

$$x=\frac{0±60\sqrt{5}}{30}$$

Now solve the equation x=\frac{0±60\sqrt{5}}{30} when ± is plus.

$$x=2\sqrt{5}$$

Now solve the equation x=\frac{0±60\sqrt{5}}{30} when ± is minus.

$$x=-2\sqrt{5}$$

The equation is now solved.

$$x=2\sqrt{5} x=-2\sqrt{5}$$