Tick (✓) the correct answer:
x2 + 4x − 21 = ?
(a) (x − 7)(x + 3)
(b) (x + 7)(x − 3)
(c) (x − 7)(x − 3)
(d) (x + 7)(x + 3)
$x^{2}+4 x-21$
$=x^{2}+7 x-3 x-21$
$=x(x+7)-3(x+7)$
$=(x-3)(x+7)$
Leave a comment
All Study Material
