Solve 32x-16x^2=12

$$32x-16 { x }^{ 2 } =12$$

Solve for x

$$x=\frac{1}{2}=0.5$$

$$x = \frac{3}{2} = 1\frac{1}{2} = 1.5$$

Steps Using Factoring By Grouping

Subtract 12 from both sides.

$$32x-16x^{2}-12=0$$

Divide both sides by 4.

$$8x-4x^{2}-3=0$$

Rearrange the polynomial to put it in standard form. Place the terms in order from highest to lowest power.

$$-4x^{2}+8x-3=0$$

To solve the equation, factor the left hand side by grouping. First, left hand side needs to be rewritten as -4x^{2}+ax+bx-3. To find a and b, set up a system to be solved.

$$a+b=8 ab=-4\left(-3\right)=12$$

Since ab is positive, a and b have the same sign. Since a+b is positive, a and b are both positive. List all such integer pairs that give product 12.

$$1,12 2,6 3,4$$

Calculate the sum for each pair.

$$1+12=13 2+6=8 3+4=7$$

The solution is the pair that gives sum 8.

$$a=6 b=2$$

Rewrite -4x^{2}+8x-3 as \left(-4x^{2}+6x\right)+\left(2x-3\right).

$$\left(-4x^{2}+6x\right)+\left(2x-3\right)$$

Factor out -2x in -4x^{2}+6x.

$$-2x\left(2x-3\right)+2x-3$$

Factor out common term 2x-3 by using distributive property.

$$\left(2x-3\right)\left(-2x+1\right)$$

To find equation solutions, solve 2x-3=0 and -2x+1=0.

$$x=\frac{3}{2} x=\frac{1}{2}$$

Steps Using the Quadratic Formula

All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. The quadratic formula gives two solutions, one when ± is addition and one when it is subtraction.

$$-16x^{2}+32x=12$$

Subtract 12 from both sides of the equation.

$$-16x^{2}+32x-12=12-12$$

Subtracting 12 from itself leaves 0.

$$-16x^{2}+32x-12=0$$

This equation is in standard form: ax^{2}+bx+c=0. Substitute -16 for a, 32 for b, and -12 for c in the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}.

$$x=\frac{-32±\sqrt{32^{2}-4\left(-16\right)\left(-12\right)}}{2\left(-16\right)}$$

Square 32.

$$x=\frac{-32±\sqrt{1024-4\left(-16\right)\left(-12\right)}}{2\left(-16\right)}$$

Multiply -4 times -16.

$$x=\frac{-32±\sqrt{1024+64\left(-12\right)}}{2\left(-16\right)}$$

Multiply 64 times -12.

$$x=\frac{-32±\sqrt{1024-768}}{2\left(-16\right)}$$

Add 1024 to -768.

$$x=\frac{-32±\sqrt{256}}{2\left(-16\right)}$$

Take the square root of 256.

$$x=\frac{-32±16}{2\left(-16\right)}$$

Multiply 2 times -16.

$$x=\frac{-32±16}{-32}$$

Now solve the equation x=\frac{-32±16}{-32} when ± is plus. Add -32 to 16.

$$x=-\frac{16}{-32}$$

Reduce the fraction \frac{-16}{-32} to lowest terms by extracting and canceling out 16.

$$x=\frac{1}{2}$$

Now solve the equation x=\frac{-32±16}{-32} when ± is minus. Subtract 16 from -32.

$$x=-\frac{48}{-32}$$

Reduce the fraction \frac{-48}{-32} to lowest terms by extracting and canceling out 16.

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

The equation is now solved.

$$x=\frac{1}{2} x=\frac{3}{2}$$

Steps for Completing the Square

Quadratic equations such as this one can be solved by completing the square. In order to complete the square, the equation must first be in the form x^{2}+bx=c.

$$-16x^{2}+32x=12$$

Divide both sides by -16.

$$\frac{-16x^{2}+32x}{-16}=\frac{12}{-16}$$

Dividing by -16 undoes the multiplication by -16.

$$x^{2}+\frac{32}{-16}x=\frac{12}{-16}$$

Divide 32 by -16.

$$x^{2}-2x=\frac{12}{-16}$$

Reduce the fraction \frac{12}{-16} to lowest terms by extracting and canceling out 4.

$$x^{2}-2x=-\frac{3}{4}$$

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

$$x^{2}-2x+1=-\frac{3}{4}+1$$

Add -\frac{3}{4} to 1.

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

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

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

Take the square root of both sides of the equation.

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

Simplify.

$$x-1=\frac{1}{2} x-1=-\frac{1}{2}$$

Add 1 to both sides of the equation.

$$x=\frac{3}{2} x=\frac{1}{2}$$