To complete the square, first the coefficient in front of the x^2 must be 1, which it is in this case. Then, take the coefficient in front of the x and divide by 2, then square that.
5/2=2.5
2.5²=6.25 or 25/4
Then add this number to both sides and simplify.
x²+5x+25/4=2+25/4
x²+5x+25/4=33/4
Factor the left side using reverse foil. Hint: the number that you are adding/subtracting by should be the number you got when you divided the coefficient of x by 2
(x+5/2)²=33/4
√(x+5/2)²=√(33/4)
x+5/2=33/4 or x+5/2= -33/4
x=23/4 or x=-43/4