Question

find $f'(3)$ for$f(x) = x² + 10x$

Answer 1

$f(x)=x^2+10x$

$\implies f'(x)=\frac{d}{dx}(f(x))=\frac{d}{dx}(x^2+10x)=2x+10$

And $f'(3)=2(3)+10=6+10=16$