Posted by **Jack** on Thursday, March 21, 2013 at 4:41pm.

Solve for B: square root b^4/25 = 4.

A.) 2

B.) +/- 5 square root 2

C.) 3

D.) +/- 2 square root 5

I don't know how to do these so please show your work.

Thank you.

- Algebra: Please help -
**Knights**, Thursday, March 21, 2013 at 4:52pm
we cross multiply or multiply both sides by 25 to get b^4 = 100

sqrt of both sides gives us sqrt b^4 = sqrt 100 =

sqrt b^2 * b^2 = 10

b^2 = 10

b = +/- sqrt 10

which is roughly equal to +/- 3.1623...

- Algebra: Please help -
**Steve**, Thursday, March 21, 2013 at 4:55pm
√(b^4/25) = 4

b^2/5 = 4

b^2 = 20

b = ±√20, but since 20=4*5,

b = ±2√5

- Algebra: Please help -
**Jack**, Thursday, March 21, 2013 at 4:57pm
So which is it?

- Algebra: Please help -
**Knights**, Thursday, March 21, 2013 at 4:59pm
woops Steve is right, I did not see the sqrt before the equation.

So we get 16 = b^4/25

Simplifying we get 25*16 = 400

b^4 = 400

b^2 = 20

so, b^2 = sqrt 2^2 * 5

so, b = +/- 2 sqrt 5

answer is D

Sorry for inconvenience

- Algebra: Please help -
**Knights**, Thursday, March 21, 2013 at 5:02pm
*Sorry for any inconveniences caused to you.

- Algebra: Please help -
**Jack**, Thursday, March 21, 2013 at 5:07pm
Thank you for all your help...I appreciate it.

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