Please do help solve the followings

Question

1) Integrate e^4 dx

2) Integrate dx/sqrt(90^2-4x^2)

3) Integrate (e^x+x)^2(e^x+1) dx

4) Integrate xe^x2 dx

e^4 is a constant.

3) let u= e^x + x
du= (e^x + 1)dx

4) let u= x du=dx
v= e^x dv= e^x dx