Question

derivada pela definição f(x)-f(x1)/delta x

Answer 1

$\underset{h\to0}{lim}\frac{(3(x+h)^2+12)-(3x^2+12)}{h}=\underset{h\to0}{lim}\frac{(3(x^2+2hx+h^2)+12)-(3x^2+12)}{h}=$ $\underset{h\to0}{lim}\frac{3x^2+6hx+h^2+12-3x^2-12}{h}=\underset{h\to0}{lim}\frac{6hx+h^2}{h}=\underset{h\to0}{lim}6x+h=6x+0=\boxed{6x}$