Solve 24=(x-8)(x-3)

$$24 = ( x - 8 ) ( x - 3 )$$

Solve for x

$$x=11$$

$$x=0$$

Steps Using the Quadratic Formula

Use the distributive property to multiply x-8 by x-3 and combine like terms.

$$24=x^{2}-11x+24$$

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

$$x^{2}-11x+24=24$$

Subtract 24 from both sides.

$$x^{2}-11x+24-24=0$$

Subtract 24 from 24 to get 0.

$$x^{2}-11x=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute 1 for a, -11 for b, and 0 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-\left(-11\right)±\sqrt{\left(-11\right)^{2}}}{2}$$

Take the square root of \left(-11\right)^{2}.

$$x=\frac{-\left(-11\right)±11}{2}$$

The opposite of -11 is 11.

$$x=\frac{11±11}{2}$$

Now solve the equation x=\frac{11±11}{2} when ± is plus. Add 11 to 11.

$$x=\frac{22}{2}$$

Divide 22 by 2.

$$x=11$$

Now solve the equation x=\frac{11±11}{2} when ± is minus. Subtract 11 from 11.

$$x=\frac{0}{2}$$

Divide 0 by 2.

$$x=0$$

The equation is now solved.

$$x=11 x=0$$

Steps for Completing the Square

Use the distributive property to multiply x-8 by x-3 and combine like terms.

$$24=x^{2}-11x+24$$

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

$$x^{2}-11x+24=24$$

Subtract 24 from both sides.

$$x^{2}-11x=24-24$$

Subtract 24 from 24 to get 0.

$$x^{2}-11x=0$$

Divide -11, the coefficient of the x term, by 2 to get -\frac{11}{2}. Then add the square of -\frac{11}{2} to both sides of the equation. This step makes the left hand side of the equation a perfect square.

$$x^{2}-11x+\left(-\frac{11}{2}\right)^{2}=\left(-\frac{11}{2}\right)^{2}$$

Square -\frac{11}{2} by squaring both the numerator and the denominator of the fraction.

$$x^{2}-11x+\frac{121}{4}=\frac{121}{4}$$

Factor x^{2}-11x+\frac{121}{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}.

$$\left(x-\frac{11}{2}\right)^{2}=\frac{121}{4}$$

Take the square root of both sides of the equation.

$$\sqrt{\left(x-\frac{11}{2}\right)^{2}}=\sqrt{\frac{121}{4}}$$

Simplify.

$$x-\frac{11}{2}=\frac{11}{2} x-\frac{11}{2}=-\frac{11}{2}$$

Add \frac{11}{2} to both sides of the equation.

$$x=11 x=0$$