Find the derivative $of$ the function using the definition $of$ derivative.

$f(x)=3\mathrm{.}5x2-x+3\mathrm{.}4$

$f\text{'}(x)=$

State the domain $of$ the function. $(Enter$ your answer $in$ interval notation.$)$

State the domain $of$ its derivative. $(Enter$ your answer $in$ interval notation.$)$