simpliy the following: (a) {[4x^2-49]/[8x^3+27]} *{ [4x^2+12x+9]/[2x^2-13x+21]} (b) {[x^2+x-6]/[x^2+7x-6]}*{[20x^2-7x-3]/[6x^2-25x+4]}*{[4x^2-11x-3]/[6x^2-19x+3]}

2 answers

Here's (a):

{[4x^2-49]/[8x^3+27]} *{ [4x^2+12x+9]/[2x^2-13x+21]}

4x^2-49 = (2x-7)(2x+7)
8x^3+27 = (2x+3)(4x^2-6x+9)
4x^2+12x+9 = (2x+3)(2x+3)
2x^2-13x+21 = (2x-7)(x-3)

Putting it all together, you can cancel the (2x-7)(2x+3) to get

(2x+7)(2x+3) / (x-3)(4x^2-6x+9)

Do (b) likewise. The key is to know how to factor these babies. Recognize differences of square and cubes.
simpliy the expression by adding like terms and write the expression in descending powers of x 4x²+11x-3x²-12+x