Factorise (2x2+13x+15)
5
(2x−3)(x−5)
(2x+3)(x+10)
(2x+3)(2x+5)
2x2+13x+15
The product of the first and last term = 15×2x2=30x2 and the sum or difference = 13 x ;
Hence 30x2=10x×3x
= 2x2+10x+3x+15 = 2x(x+5)+3(x+5) = (2x+3)(x+5)
Factorise 2x2+13x+15
Using the remainder Theorem, factorise each of the following completely: (i) 3x3+2x2−19x+6 (ii)2x3+x2−13x+6 (iii) 3x3+2x2−23x−30 (iv) 4x3+7x2−36x−63 (v) x3+x2−4x−4.