Solve the equation √x = 15

Answers:

{3.9, -3.9}
{3.9}
{255, -255}
{255}

Question

Solve the equation √x = 15

Answers:

{3.9, -3.9}
{3.9}
{255, -255}
{255}

campbell_st · Answer

square both sides of the equation to find x.... 

and you have either made a typo... or the answers don't match the question.

yttrium · Answer

One of the choices matched. And what you need to do is to cancel the sqrt sign first by squaring the whole expression as @campbell_st  said. When we say square the whole equation, you must multiply the expression by itself. Therefore, it should be sqrt(x) time sqrt(x) = 15 times 15. There you will get the answer.

anonymous · Answer

we need x , so we should square both side then we'll have x and square of the number.. 
and we solve it :)

anonymous · Answer

square both sides to receive x = 15^2. given that you are reversing a sqrt, you must show that the answer could be positive or negative so it would be x = + or -15^2. x has two solutions. so given that 15 squared is 225, you would write your solution as x = {225, -225}

campbell_st · Answer

@cravescoffee&catharsis 

just a quick question re your solution 

$$x = \pm 225$$

how is 

$$\sqrt{-225} = 15$$

you should always check the appropriateness of an answer.