Question:

The sum of absolute maximum and absolute minimum values of the function \(f(x)=\left|4x^{2}+3x-10\right|+x^{2}-2x+5,\ x\in[-3,1]\) is ________.

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Find where \(4x^2+3x-10\) changes sign, write \(f\) piecewise on \([-3,1]\), and compare the values at the end points, break point and vertex.
Updated On: Nov 12, 2026
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Correct Answer: 44

Solution and Explanation

\(4x^2+3x-10=(4x-5)(x+2)\), so it is zero at \(x=-2\) and \(x=\frac54\). On \([-3,1]\) it is positive for \(-3\le x<-2\) and negative for \(-2<x\le 1\).
For \(-3\le x\le -2\): \(f(x)=5x^2+x-5\). Its vertex is at \(x=-\frac1{10}\), outside this interval, so \(f\) is decreasing here, from \(f(-3)=37\) to \(f(-2)=13\).
For \(-2\le x\le 1\): \(f(x)=-3x^2-5x+15\). Its vertex is at \(x=-\frac56\) with \(f\left(-\frac56\right)=\frac{205}{12}\approx 17.08\).
Values to compare: \(f(-3)=37\), \(f(-2)=13\), \(f\left(-\frac56\right)\approx17.08\), \(f(1)=7\).
Absolute maximum = 37 and absolute minimum = 7.
Sum = 37 + 7 = 44.
Answer: 44
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