Algebra
posted by Jeconiah .
simpliy the following: (a) {[4x^249]/[8x^3+27]} *{ [4x^2+12x+9]/[2x^213x+21]} (b) {[x^2+x6]/[x^2+7x6]}*{[20x^27x3]/[6x^225x+4]}*{[4x^211x3]/[6x^219x+3]}

Here's (a):
{[4x^249]/[8x^3+27]} *{ [4x^2+12x+9]/[2x^213x+21]}
4x^249 = (2x7)(2x+7)
8x^3+27 = (2x+3)(4x^26x+9)
4x^2+12x+9 = (2x+3)(2x+3)
2x^213x+21 = (2x7)(x3)
Putting it all together, you can cancel the (2x7)(2x+3) to get
(2x+7)(2x+3) / (x3)(4x^26x+9)
Do (b) likewise. The key is to know how to factor these babies. Recognize differences of square and cubes.