Help Please?

1.30√-25 x 8√-49

2. 6√-64 + 12√-36

3. 4√-13 - 6√-13

5 answers

30√-25 x 8√-49
= 30√25√-1 x 8√49√-1
=150√-1 x 56√-1
= 8400 (-1)
= -8400 , remember that √-1 x √-1 = i x i = i^2 = -1

do the others the same way, let me know what you got
I'm Doing Problem 2 Right Now .
But I'm Stuck How Did You Get 150 In the 3rd Line?
30√25√-1 x 8√49√-1
= 30 x 5 x √-1 x 8 x 7 x √-1
= 150 x √-1 x 56 x √-1
= 8400 x i^2
= ....
Oh Okay .
I Tried The Other Two Problems.
For #1 I Got 120 As My Answer.
For #2 I Got 37 As My Answer.
Nope:

6√-64 + 12√-36 = 6*8i + 12*6i = 120i

4√-13 - 6√-13 = (4-6)√-13 = -2√13 i