(i) x^(2)+9x+18=x^(2)+6x+3x+18 {by splitting middle term] =x(x+6)+3(x+6)=)x+3(x+6) (ii) 6x^(2)+7x-3=6x^(2)+9x-2x-3 [by splitting middle term] (iii) 2x^(2) -7x -15=2x^(2) -10x+3x-15 [by splitting middle term] =2x(x-5)+3(x-5)=(2x+3)(x-5)