WAEC - Mathematics (1989 - No. 9)
Factorize the following expression; 2x2 + x - 15
(2x+5)(x-3)
(2x-5)(x+3)
(2x-5)(x-3)
(2x-3)(x+5)
(2x+5)(x+3)
คำอธิบาย
2x 2 + x - 15; 2x 2 + 6x - 5x - 15
(2x 2 + 6x) - ( 5x + 15)
2x(x + 3) - 5(x + 3)
(2x - 5)(x + 3)
(2x 2 + 6x) - ( 5x + 15)
2x(x + 3) - 5(x + 3)
(2x - 5)(x + 3)