Solve 16-4x^2=0

$$16 - 4 x ^ { 2 } = 0$$

Solve for x

$$x=2$$

$$x=-2$$

Steps by Finding Square Root

Subtract 16 from both sides. Anything subtracted from zero gives its negation.

$$-4x^{2}=-16$$

Divide both sides by -4.

$$x^{2}=\frac{-16}{-4}$$

Divide -16 by -4 to get 4.

$$x^{2}=4$$

Take the square root of both sides of the equation.

$$x=2 x=-2$$

Steps Using the Quadratic Formula

Quadratic equations like this one, with an x^{2} term but no x term, can still be solved using the quadratic formula, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, once they are put in standard form: ax^{2}+bx+c=0.

$$-4x^{2}+16=0$$

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

$$x=\frac{0±\sqrt{0^{2}-4\left(-4\right)\times 16}}{2\left(-4\right)}$$

Square 0.

$$x=\frac{0±\sqrt{-4\left(-4\right)\times 16}}{2\left(-4\right)}$$

Multiply -4 times -4.

$$x=\frac{0±\sqrt{16\times 16}}{2\left(-4\right)}$$

Multiply 16 times 16.

$$x=\frac{0±\sqrt{256}}{2\left(-4\right)}$$

Take the square root of 256.

$$x=\frac{0±16}{2\left(-4\right)}$$

Multiply 2 times -4.

$$x=\frac{0±16}{-8}$$

Now solve the equation x=\frac{0±16}{-8} when ± is plus. Divide 16 by -8.

$$x=-2$$

Now solve the equation x=\frac{0±16}{-8} when ± is minus. Divide -16 by -8.

$$x=2$$

The equation is now solved.

$$x=-2 x=2$$