Find the difference quotient and simplify your answer. f (x) = 7x - x2, f (7 + h) - f (7) h, h ≠ 0

Whatever is inside of the (), simply plug that digit into the x-values for f (x)

So: f (x) = 7x - x^2, and f (7+h) - f (7)

= [7 (7+h) - (7+h) ^2] - [7 (7) - (7) ^2]

= [49+7h - 49+14h+h^2] - [49-49]

= 49-49 + 7h+14h + h^2 = h^2 + 21h =

h (h+21), h (h+21) = 0

h=0 ... But it stated h cannot = 0

So h+21 = 0, h = - 21