How to find the derivative of F, in the f(x) = x2 + 4x. and what is the point of the graph of F where the tangent line to the curve is horizontal

Answer 1

Derivative is 2x+4.

F is horizontal where the derivative is 0: 2x+4 = 0

x = -4/2 = -2.

Y: (-2)^2 +4(-2) = 4 -8 = -4

The point is (-2,-4)