## katlin95 2 years ago solve for x: sqrt x^2-x-5=5 A. -5 B. -6 C. 6 D. -5, 6

1. katlin95

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2. cwrw238

your question isa bit confusing do you mean square root oh ok

3. phi

what do you get if you square both sides of the equation ?

4. katlin95

not sure..

5. phi

how about the right side of the = sign ? what is 5*5 ?

6. katlin95

25

7. phi

on the left use the rule that a sqrt times itself makes the square root "go away" in other words, sqrt(x) * sqrt(x) is x no matter how complicated x is.

8. katlin95

-6

9. phi

All we want is the left side squared. here are some examples sq rt(1+2+3)* sq rt (1+2+3) = 1+2+3 or sq rt(x^2 * 30y)* sq rt (x^2*30y) = x^2*30y what is sq rt (x^2-x-5) * sq rt (x^2-x-5) ?

10. phi

do you need more examples of what happens when you square a square root ?

11. katlin95

no:)

12. phi

in that case what is sq rt (x^2-x-5) * sq rt (x^2-x-5) ?

13. katlin95

-5,6

14. phi

I have not solved this, so I don't know off hand. You can learn to solve it or you can try substituting in possible answers and see if they work.

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