If (x - 1) and (x + 2) are factors of x^3 + ax^2 + bx -... – Algebra

Algebrahard · Past Paper

If (x - 1) and (x + 2) are factors of x^3 + ax^2 + bx - 2, find a and b.

Aa=2, b=-1

Ba=1, b=-2

Ca=2, b=1

Da=-2, b=1

✓ Correct Answer: A — a=2, b=-1

P(1)=1+a+b-2=0 => a+b=1. P(-2)=-8+4a-2b-2=0 => 4a-2b=10 => 2a-b=5. Solve: 3a=6 => a=2, b=-1.

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