# How do you solve #sqrt (x+9)=4#?

##### 2 Answers

Jan 27, 2016

To solve equations that involve radicals, you must square both sides of the equation.

#### Explanation:

x + 9 = 16

x = 16 - 9

x = 7

With radical equations it is alway vital to check your solutions in the original equation, since extraneous solutions may arise. You must especially be careful of them in radical-quadratic equations, where two solutions often appear but oftentimes only one is the correct solution.

**Practice exercises:**

- Solve each equation. Watch out for extraneous solutions.

a)

b)

c)

Jan 30, 2016

#### Explanation:

Square both sides: