Posted by **Bob** on Thursday, August 16, 2012 at 8:40am.

Help Please?

1.30√-25 x 8√-49

2. 6√-64 + 12√-36

3. 4√-13 - 6√-13

- Algebra2 -
**Reiny**, Thursday, August 16, 2012 at 8:48am
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

- Algebra2 -
**Bob**, Thursday, August 16, 2012 at 9:19am
I'm Doing Problem 2 Right Now .

But I'm Stuck How Did You Get 150 In the 3rd Line?

- Algebra2 -
**Reiny**, Thursday, August 16, 2012 at 9:39am
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

= ....

- Algebra2 -
**Sara**, Thursday, August 16, 2012 at 9:50am
Oh Okay .

I Tried The Other Two Problems.

For #1 I Got 120 As My Answer.

For #2 I Got 37 As My Answer.

- Algebra2 - Sara -
**Steve**, Thursday, August 16, 2012 at 11:21am
Nope:

6√-64 + 12√-36 = 6*8i + 12*6i = 120i

4√-13 - 6√-13 = (4-6)√-13 = -2√13 i

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