Factorisation of Quadratic Polynomials- Middle Term Splitting
Examine wheth...
Question
Examine whether x + 2 is a factor of x3+3x2+5x+6 and 2x + 4.
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Solution
The zero of x + 2 is -2. Let p(x) = x3+3x2+5x+6 and s(x) = 2x + 4
Then, p(−2)=(−2)3+3(−2)2+5(−2)+6
= -8 + 12 - 10 + 6 = 0
So, by the Factor Theorem, x + 2 is a factor of x3+3x2+5x+6.
Again, s(-2) = 2(-2)+4 = 0
So, x + 2 is a factor of 2x + 4