From: Mr.DJ7 - Public Text WindowHello, I'm having trouble on this question, because my book didn't describe the solution properly:

For Each Function the point given is the maximum or minimum.

Use the difference quotient to verify that the slope of the tangent at this point is zero.

1. f(x)=0.5x^2 +6x + 7.5 Cords (-6, -10.5)

I also need help with this question:

Use an algebraic strategy to verify that the point given for each function is either a maximum or a minimum.

f(x)= x^2 - 4x + 5 Cords (2, 1)