MCQ
$\left(x^2-4 x-21\right)=?$
- ✓$(x - 7) (x + 3)$
- B$( x - 7) ( x - 3)$
- C$(x + 7) (x + 3)$
- D$(x + 7) (x - 3)$
✓
Answer
Correct option: A.
$(x - 7) (x + 3)$
$\left(x^2-4 x-21\right)=x^2-7 x+3 x-21$
$=x(x-7)+3(x-7)$
$=(x-7)(x+3)$
$=x(x-7)+3(x-7)$
$=(x-7)(x+3)$
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