f(x+h)-f(x)/h for f(x)= 4x+9 and simplify.

Answer 1

f(x+h)-f(x)/h
= (4(x+h) + 9 - (4x+9))/h
= 4x + 4h + 9 - 4x - 9)/h
= 4h/h
= 4 , h not equal to zero

Answer 2

Thank you for the help!