GCSE maths help please (embarassed face)

[princessparty]

DS1 was doing some maths revison last night and asked me for help with a question.I should really have been able to help DS1 with this , but it's 27 years since I studied maths!
The question was to solve a quadratic equation expressing the answer in surd form
so question was x2+2x-10=0
Thinking about it again this morning

could you do it by
1 completing the square
2 square rooting both sides
3 rearranging to get x on it's own

many thanks to anyone who can help!

not sure what surd form is, but my first response to such algebraic questions is option 3 - get x on its own.

You need to use the quadratic formula. For the quadratic ax^2+bx+c=0 you do

x=(-b±√(b^2-4ac))/2a
so for the one above you would do
x= (-2±√(2^2-4x1x-10))/2x1
= (-2±√(4+40)/2
= (-2±√44)/2
=(-2+√44)/2 or (-2-√44)/2
It can be simplied further but that is sufficient at GCSE. BTW this is equivalent to completing the square but quadratic formula is on formula sheet so easier

AAAgghh
formatting hasnt worked
√ should be + or - square root of

will retry later!

Thanks very much for your help

We came to x= -1+/-sq root of 11
Is that the same thing? I think it is?
using the formula does seem to be easier but for some reason they've told the kids it's better to 'complete the square' if they can.No idea why!!!

yes it is you divide by 2. root 44 is root(4 x 11) which is 2 x root 11
I have no idea who you would complete the square - too much potential for mistakes!

OMG! You again!!!
F off there's a dear.