Find F'(x)

Question

Original equation:

F(x)= definite integral of x+3 to 0 (10t+1) dt

Answer 1

Whoops, I meant:

f(x)=definite integral (10t+1)dt from x+3 to 0

Answer 2

int (10t+1) dt = 5 t^2 + t
at t = 0 that is 0
at t = x+3 that is 5(x+3)^2 +(x+3)
subtract
F(x) = - 5(x+3)^2 - x - 3

now do d/dx
-10(x+3) - 1
or
-10 x - 31