Hi, having troubles once again, not a foggy what i'm doing wrong

question is

'by completing the square, solve the quadratic equation, giving your answer in surd form'

sorry i don't know how to put in that math notation stuff.

: xsquared + 3x - 5 = 0

this is where i got

(x + 3/2)squared - 29/4 = 0

x = -3/2 +or- squarerootof 29/4

whereas they get

x = -3/2 +or- squarerootof 29/2

other questions where i was expecting the last bit (the squareroot-of-bit) to be Something/4, the book was saying Something/2. i just dont see how they got there. please help