Đáp án:
$\begin{array}{l}
a)y = {x^2} + {x^4} - {x^3} + {x^2} - x + 14\\
= {x^4} - {x^3} + 2{x^2} - x + 14\\
\Rightarrow y' = 4{x^3} - 3{x^2} + 4x - 1\\
b)y = {x^5} + 14{x^4} - {x^3} + 14{x^2} - 14x - 14\\
= 5{x^4} + 56{x^3} - 3{x^2} + 28x - 14\\
c)f\left( x \right) = \left( {x + 14} \right)\left( {{x^3} + {x^2} + x - 14} \right)\\
f'\left( x \right) = \left( {{x^3} + {x^2} + x - 14} \right)\\
+ \left( {x + 14} \right)\left( {3{x^2} + 2x + 1} \right)\\
= 4{x^3} + 45{x^2} + 30x\\
d)y = \frac{{x - 14}}{{x - 14}} = 1\\
\Rightarrow y' = 0
\end{array}$
