Hello,Originally Posted by cinder
use u(x) = 2x+3. Then du/dx = 2. That means du = 2*dx.
So you could use the substitution method if there are the factor 2:
Now you can re-substitute and you'll get:
Factorize (x^2-1) = (x+1)(x-1). Then you can cancel (x-1) and you'll get:
From here on you know what to do!