I think you need to use binomial theorem
Find the constant term in the expansion of (2z - 1/(z*sqrt(z)) + 1)^4.
To get a constant term, we need the z's to cancel out. Notice that we can't eliminate the z with less than 4 2z's and 1z√z's. The closest we can do is (2z)3×(1z√z)2, but that uses 5, so it doesn't work.
Thus, the only constant term will be the 1 multiplied by itself 4 times, which is 14=1