hope this helps im sure some one else would be better at this than me.

you started off right but as your doing a quadratic you need to get your formula into a form that looks like

0 = ax^2+bx+c

so multiplying by 2 worked but then you needed to expand the bracket on the right hand side and rearrange everything to one side so you have 0 =

once thats done you just use the quadratic formula giving you two results for x