Question

Simplifique f(x+h)-f(x) / h sendo f(x) igual a x²+3x

Answer 1

$f(x+h)=(x+h)^2+3(x+h) = x^2+2xh+h^2+3x+3h \Leftrightarrow \\ \\ \Leftrightarrow f(x+h)-f(x)=(x^2+2xh+h^2+3x+3h)-(x^2+3x)= \\ \\ =2xh +h^2 +3h \Leftrightarrow \left (f(x+h)-f(x))/h=2x+3+h$