Tolong di jawab + cara nya

b). f(x)=x⁴-3x³+7x+5
f'(x)=4x³-6x+7
c). f(x)=(x-3)(x+5)
f(x)=U.V => f'(x)=U'V+V'U
f'(x)=1(x+5)+1(x-3)=x+5+x-3=3x+2
d). f(x)=(1/4)x⁴-(1/3)x³-25
f'(x)=x³-x²