Solve 0=x^2-x+156

$$0 = x ^ { 2 } - x + 156$$

Solve for x (complex solution)

$$x=\frac{1+\sqrt{623}i}{2}\approx 0.5+12.479983974i$$

$$x=\frac{-\sqrt{623}i+1}{2}\approx 0.5-12.479983974i$$

Steps Using the Quadratic Formula

Swap sides so that all variable terms are on the left hand side.

$$x^{2}-x+156=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -1 for b, and 156 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-\left(-1\right)±\sqrt{1-4\times 156}}{2}$$

Multiply -4 times 156.

$$x=\frac{-\left(-1\right)±\sqrt{1-624}}{2}$$

Add 1 to -624.

$$x=\frac{-\left(-1\right)±\sqrt{-623}}{2}$$

Take the square root of -623.

$$x=\frac{-\left(-1\right)±\sqrt{623}i}{2}$$

The opposite of -1 is 1.

$$x=\frac{1±\sqrt{623}i}{2}$$

Now solve the equation x=\frac{1±\sqrt{623}i}{2} when ± is plus. Add 1 to i\sqrt{623}.

$$x=\frac{1+\sqrt{623}i}{2}$$

Now solve the equation x=\frac{1±\sqrt{623}i}{2} when ± is minus. Subtract i\sqrt{623} from 1.

$$x=\frac{-\sqrt{623}i+1}{2}$$

The equation is now solved.

$$x=\frac{1+\sqrt{623}i}{2} x=\frac{-\sqrt{623}i+1}{2}$$

Steps for Completing the Square

Swap sides so that all variable terms are on the left hand side.

$$x^{2}-x+156=0$$

Subtract 156 from both sides. Anything subtracted from zero gives its negation.

$$x^{2}-x=-156$$

Divide -1, the coefficient of the x term, by 2 to get -\frac{1}{2}. Then add the square of -\frac{1}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.

$$x^{2}-x+\left(-\frac{1}{2}\right)^{2}=-156+\left(-\frac{1}{2}\right)^{2}$$

Square -\frac{1}{2} by squaring both the numerator and the denominator of the fraction.

$$x^{2}-x+\frac{1}{4}=-156+\frac{1}{4}$$

Add -156 to \frac{1}{4}.

$$x^{2}-x+\frac{1}{4}=-\frac{623}{4}$$

Factor x^{2}-x+\frac{1}{4}. In general, when x^{2}+bx+c is a perfect square, it can always be factored as \left(x+\frac{b}{2}\right)^{2}.

$$\left(x-\frac{1}{2}\right)^{2}=-\frac{623}{4}$$

Take the square root of both sides of the equation.

$$\sqrt{\left(x-\frac{1}{2}\right)^{2}}=\sqrt{-\frac{623}{4}}$$

Simplify.

$$x-\frac{1}{2}=\frac{\sqrt{623}i}{2} x-\frac{1}{2}=-\frac{\sqrt{623}i}{2}$$

Add \frac{1}{2} to both sides of the equation.

$$x=\frac{1+\sqrt{623}i}{2} x=\frac{-\sqrt{623}i+1}{2}$$