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Question
Use factor theorem to determine whether x + 3 is factor of x 2 + 2x − 3 or not.
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Solution
Let p(x) = x2 + 2x − 3.
Divisor = x + 3
∴ Let x = −3
∴ p(−3) = (−3)2 + 2 × (−3) − 3
= 9 − 6 − 3
= 0
So, by factor theorem, (x + 3) is a factor of x2 + 2x − 3.
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