Here you need to use the quadratic formula, it cannot be solved by expanding out the brackets. In the formulae for which can be found on the formulae sheet. In this case a=5, b=8 and c=2.
This gives: x=(-8±√(82-(4x5x2)))/(2x5)
This simplifies to x=(-8±√24)/10
The plus or minus sign shows there are two possible solutions.
For x=(-8+√24)/10, x=0.3
For x=(-8-√24)/10, x=-1.3