Take e^x out from the denominator.

Let, e^-x + 2 = t

Differentiating both sides with respect to x

-dt = e^-x dx

Use formula

Y = -ln t + c

Again, put e^-x + 2 = t

Y = -ln(e^-x + 2) + c

Note: Don’t forget to replace t with the function of x at the end of solution. Always put constant c with indefinite integral.