Solve 2x^2+8=5

$$2 x ^ { 2 } + 8 = 5$$

Solve for x (complex solution)

$$x=-\frac{\sqrt{6}i}{2}\approx -0-1.224744871i$$

$$x=\frac{\sqrt{6}i}{2}\approx 1.224744871i$$

Steps by Finding Square Root

Subtract 8 from both sides.

$$2x^{2}=5-8$$

Subtract 8 from 5 to get -3.

$$2x^{2}=-3$$

Divide both sides by 2.

$$x^{2}=-\frac{3}{2}$$

The equation is now solved.

$$x=\frac{\sqrt{6}i}{2} x=-\frac{\sqrt{6}i}{2}$$

Steps Using the Quadratic Formula

Subtract 5 from both sides.

$$2x^{2}+8-5=0$$

Subtract 5 from 8 to get 3.

$$2x^{2}+3=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 2 for a, 0 for b, and 3 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{0±\sqrt{0^{2}-4\times 2\times 3}}{2\times 2}$$

Square 0.

$$x=\frac{0±\sqrt{-4\times 2\times 3}}{2\times 2}$$

Multiply -4 times 2.

$$x=\frac{0±\sqrt{-8\times 3}}{2\times 2}$$

Multiply -8 times 3.

$$x=\frac{0±\sqrt{-24}}{2\times 2}$$

Take the square root of -24.

$$x=\frac{0±2\sqrt{6}i}{2\times 2}$$

Multiply 2 times 2.

$$x=\frac{0±2\sqrt{6}i}{4}$$

Now solve the equation x=\frac{0±2\sqrt{6}i}{4} when ± is plus.

$$x=\frac{\sqrt{6}i}{2}$$

Now solve the equation x=\frac{0±2\sqrt{6}i}{4} when ± is minus.

$$x=-\frac{\sqrt{6}i}{2}$$

The equation is now solved.

$$x=\frac{\sqrt{6}i}{2} x=-\frac{\sqrt{6}i}{2}$$