Question

if f(x)=x-5,find f(h),f(x+h) and f(x+h)-f(x)/h where h ∉0

Answer 1

If f(x) = x - 5, then

f(h) = h - 5

f(x + h) = (x + h) - 5

(f(x + h) - f(x))/h = (((x + h) - 5) - (x - 5))/h

(f(x + h) - f(x))/h = (x + h - 5 - x + 5)/h

(f(x + h) - f(x))/h = h/h

(f(x + h) - f(x))/h = 1

since h ≠ 0.