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Find the range of the function

h(x)=5x2+20x+33x2+4x+7
Enter your answer in interval notation.

 
 Mar 29, 2025
 #2
avatar+18 
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Ok, I found the answer.

We can use polynomial long division to simplify: 

5x2+20x+33x2+4x+7=52x2+4x+7

Then, h(x)<5, and we can find the minimum by completing the square on the quadratic.

x2+4x+7=(x+2)2+3,

so the minimum is 3. Hence, the least possible value of h(x) is 133, and the range is h(x)[133,5)

 Mar 30, 2025

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