JAMB - Mathematics (2015 - No. 30)
Solve x2 − 2x − 3 = 0
x = 2 or 1
x = 3 or -1
x = 1 or 0
x = 1 or 2
Giải thích
x2 − 2x − 3 = 0
−3x + x = − 2x
− 3x × x = − 3x2
(x2 − 3x)(x − 3) = 0
(x − 3)(x + 1) = 0
Either (x − 3) = 0 or (x + 1) = 0
x = 3 or − 1
−3x + x = − 2x
− 3x × x = − 3x2
(x2 − 3x)(x − 3) = 0
(x − 3)(x + 1) = 0
Either (x − 3) = 0 or (x + 1) = 0
x = 3 or − 1