Solve: $x ^ { 2 } - 3 x - 40

Name: Solve: $x ^ { 2 } - 3 x - 40 < 0$ A) $( - \infty , - 3 )$ B) $( - 5 , \infty )$ C) $( - 5,8 )$ D) $( - \infty , 8 )$ E) $( 8 , \infty )$
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Question

Solve: $x ^ { 2 } - 3 x - 40 < 0$
A) $( - \infty , - 3 )$
B) $( - 5 , \infty )$
C) $( - 5,8 )$
D) $( - \infty , 8 )$
E) $( 8 , \infty )$

Quizplus · Accepted Answer

First, factor the quadratic equation: $x^2 - 3x - 40 = (x + 5)(x - 8)$. The roots are $x = -5$ and $x = 8$. The inequality $x^2 - 3x - 40 < 0$ is satisfied between the roots, so the correct interval is $(-5, 8)$.

Solve x2−3x−40<0x ^ { 2 } - 3 x - 40 < 0x2−3x−40<0

Solve $x ^ { 2 } - 3 x - 40 < 0$