Lucifer's 3rd Rule
Lucifer's 3rd rule: Antiderivatives can be done one sum or difference at a time, but you only need one constant of integration.
For instance:
Now apply Lucifer's 1st Rule, and we are done:
The last bit of this is the antiderivative. In other words
F(x)=x^3+x^2-5x+c
is the antiderivative of f(x)=3x^2+2x-5x.
The fact that there is only one constant of integration in F(x) (instead of 3) is what is meant by "you only need one constant of integration."