Question

im having a problem understanding integration by substitution. For intance, ∫4xe^(x^2+3)dx. The answer is 2e^(x^2+3) and I am not sure where the 2 comes from.

Answer 1

put x^2+3=t so that 2x dx=dt that eq becomes int 2e^t dt =2e^t so that 2 comes in answer.