Question

Is f(x)=x3+2x2−x−2x+3 increasing or decreasing at x=−2?

Answer 1

$x ^{3} + 2x {}^{2} - x - 2x + 3 \\ ( - 2) {}^{3} + 2( - 2) {}^{2} + 3 \\ - 8 + 8 + 3 \\ = 3$

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