# How do you solve sqrta+11=21 and check your solution?

Apr 18, 2017

$a = 100$

#### Explanation:

Subtract $11$ from both sides

$\sqrt{a} \cancel{+ 11 - 11} = 21 - 11$

$\sqrt{a} = 10$

Square both sides

${\left(\sqrt{a}\right)}^{2} = {10}^{2}$

$a = 100$

To check the solution substitute this value ($100$) instead of $a$ in the equation and see if it will give you $21$

$\sqrt{\textcolor{red}{a}} + 11 = 21$

$\sqrt{\textcolor{red}{100}} + 11 = 21$

$10 + 11 = 21$

$21 = 21$

So the solution is correct

Apr 18, 2017

The answer is $a = 100$

#### Explanation:

To get "a" by itself you want to subtract 11 from both sides:

$\sqrt{a} + 11 - 11 = 21 - 11$

So now the equation is:

$\sqrt{a} = 10$

Since you want to get "a" by itself, you want to now square both sides of the equation to get rid of the square root:

${\sqrt{a}}^{2} = {10}^{2}$

This is equal to:

$a = 100$

If you have any questions, feel free to comment!