+0  
 
0
36
2
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What is the maximum value of 4(x + 7)(2 + x) , over all real numbers x?

 May 24, 2021
 #1
avatar+176 
+1

Did you mean (2-x)? If you did, then the max is 81 at x=-5/2.

 May 24, 2021
 #2
avatar+32652 
+1

4 ( x+7)(x+2)    expand

4 ( x^2 +9x + 14)

 

4x^2 + 36x + 56     is a bowl shaped parabola        max value =  + infinity

 

 

MIN value occurs at  - b/ 2a =   - 36/8 = - 4.5    use this value of 'x' in the equation to calculate the min value

 May 24, 2021
edited by ElectricPavlov  May 24, 2021

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