Algebraic Division. Help appreciated.?

Question

(b^2 - 25) / (b + 5)^2 Divided by (2b + 10) / (4b + 20)


Alrighty, that's it. Whenever I worked it out......Somehow I came out with (-1) / (40b + 2)

It doesn't look right though.

Answer 1

(b² - 25) can be factored as the difference of squares.

[(b + 5)(b - 5)/(b+5)²] / [2(b+5) / 4(b+5)]

= [(b-5)/(b+5)] / [(b+5)²/2]

To divide fractions, invert and multiply:

= [(b-5)/(b+5)] [2/[(b+5)²]

= 2(b-5)/(b+5)

Answer 2

(b^2 - 25) / (b + 5)^2 * (4b + 20) /(2b + 10)

=(b-5)(b+5)/(b+5)(b+5) * 4(b+5)/2(b+5)

=2(b-5)/(b+5)