Math question

Test Preparation
1

<p>Hey guys,
I was doing a math problem, but it seems to have two answers, one positive and one negative, and I'm confused which one it is.
The question is:
what is sqrt(-4) * sqrt (-25)?</p>

<p>One way to do is 2i<em>5i= -10
Another way is sqrt(-4</em>-25)= sqrt(100)= 10.
Which one is the correct answer?</p>

2

<p>The answer is -10. When you are working with multiple imaginary square roots, you must first solve them out separately. So in this case, you would first solve for 2i and then 5i, THEN multiply them to get 10i^2 = -10. I learned this in class earlier this year.</p>