MCQ
If $x + 3$ is a factor of $x^2 - ax - 15, $ then $a =$
- A$-5$
- ✓$-2$
- C$5$
- D$3$
✓
Answer
Correct option: B.
$-2$
Put $x - 3 = 0,$ then $x = 3$
Therefore, value of $x^2 - ax - 15$ at $x = 3$ is zero
$⇒ 3^2 - 3a - 15 = 0$
$⇒ -6 - 3a = 0$
$⇒ a = -2$
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