(1)X^2+14X-15 =(x+15)(x-1)
(2) X^2-14X-15=(x-15)(x+1)
(3) X^2+X-6 =(x+3)(x-2)
(4)X^2-5X-6=(x-3)(x+2)
(5)X^+3X-10 =(x+5)(x-2)
(6)X^-8X-20 =(x-10)(x+2)
(7)X^2-4X-21=(x-7)(x+3)
(8)X^2+3X-18=(x+6)(x-3)