How do you factor #15x^2 – 25x – 60#?

1 Answer
Apr 5, 2016

Answer:

#15x^2-25x-60=5(3x+4)(x-3)#

Explanation:

To factorize a polynomial of general form #ax^2+bx+c#, one should divide middle term #bx# in two parts, whose sum is #b# and product is #axxc#.

So for #15x^2-25x-60#, we should divide #-25x# in two parts which add up to #-25# and whose product is #15xx(-60)=-900#.

A few trial indicate them to be #-45# and #20#. Hence

#15x^2-25x-60=15x^2-45x+20x-60# or

#15x(x-3)+20(x-3)# or

#(15x+20)(x-3)# or #5(3x+4)(x-3)#