1). f(x)=5х^6+3x^4+3x^3+x+2
f'(x)=30x^5+12x^3+6x^2+1
2). f(x)=(2x+1)*(3x+5)
f'(x)=(2x+1)'*(3x+5)+(2x+1)*(3x+5)'=2(3x+5)+3(2x+1)=6x+10+6x+3=12x+13
3). f(x)=(2x+1)/(x+3)=((2x+1*(x+3)-(x+3)*2x+1))/(x+3)^2=(2(x+3)-(2x+1))/(x+3)^2=(2x+3-2x-1`)/(x+3)^2=2|(x+3)^2