Solve sqrt{4x+72}-9=-3

$$\sqrt { 4 x + 72 } - 9 = - 3$$

Solve for x

$$x=-9$$

Steps for Solving Radical Equations

Add 9 to both sides of the equation.

$$\sqrt{4x+72}-9-\left(-9\right)=-3-\left(-9\right)$$

Subtracting -9 from itself leaves 0.

$$\sqrt{4x+72}=-3-\left(-9\right)$$

Subtract -9 from -3.

$$\sqrt{4x+72}=6$$

Square both sides of the equation.

$$4x+72=36$$

Subtract 72 from both sides of the equation.

$$4x+72-72=36-72$$

Subtracting 72 from itself leaves 0.

$$4x=36-72$$

Subtract 72 from 36.

$$4x=-36$$

Divide both sides by 4.

$$\frac{4x}{4}=-\frac{36}{4}$$

Dividing by 4 undoes the multiplication by 4.

$$x=-\frac{36}{4}$$

Divide -36 by 4.

$$x=-9$$