How do you multiply #(a^2-a-12)/(a^2-5a+4)*(a^2+2a-3)/(a^2+a-6)#?
You start by first factorising the quatratic polynomials
After cancelling out all the like terms above and below the bar, we are left with:
You could just multiply the numerator and denominator polynomials separately (this would answer the question and if this is what is required please re-post)
it is easier if you factor your polynomials and simplify: