Question

If x² = 20, what is the value of x?
1) +√10
2) + √20
3) ±10
4) +40​

Answer 1

Your second chose is your answer

Answer 2

2) ± √20

Explanation:

When square rooting an equation to solve for a variable, there are 2 solutions.

Solving For x

In order to solve for any variable, you have to isolate it. In this case, we can isolate the variable by square rooting both sides. If you square root a constant while solving an equation, you must add a plus or minus sign.

A plus or minus sign shows that the number may be either negative or positive. For this equation, the answer is both -√20 and +√20.

Checking the Solution

To make sure we are right, we can plug -√20 and +√20 into the equation.

• 
  `(-√(20) )^(2)=20`
• 
  `(√(20) )^(2)=20`

As you can see, both -√20 and +√20 equal 20 when squared. This is why you must add the plus or minus sign when square rooting a constant.