View Full Version : Simplify this fraction (simplifying rational expressions)

06-09-2006, 03:58 AM
Not sure if this is the right section since I don't think this is "introductory algebra" but oh well.

I've been trying to figure out this problem for a while now but I'm not sure how to do it, could someone explain?

64a^3 + b^3 / 16a^2b^2 - 4ab^3 + b^4
___________ _____________________
16a^2 - b^2 ... 4a^2 - ab + 12a -3b

I had a few of these which were multiplication, so I just factorised them and cancelled out to simplify. Tried the same on this but it doesn't work...

P.S Ignore the dots, it was the only way I could get it set out properly.

06-09-2006, 08:50 AM
Why have you got a division sign in top line? Is that a double division?

Anyway, you need to factor the terms, like:
4a^2 - ab + 12a - 3b = (4a - b)(a + 3)

If it's a double division, then show like this, INCLUDING brackets:

[(64a^3 + b^3) / (16a^2 - b^2)] / [(16a^2b^2 - 4ab^3 + b^4) / (4a^2 - ab + 12a - 3b)]

You can then turn that into a multiplication, same way as:
(a / b) / (c / d) = (a / b)(d / c)