Hi, 

where the function is increasing and where it is decreasing.

f(x) = -x^2 - 8x

Taking the 1st derivative:

 f'(x) =  -2x - 8   

 f'(x) > 0 when x < -4  and  f'(x)< 0 when x > -4

function is increasing when x < -4 and  is decreasing when x >-4



 



           



 

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