# Find rational numbers A & B given the attached formula

Please check the image posted. I don't think this is all that complicated, but I've not studied maths for like 10 years & I'm currently on a refresher course, I keep going around in circles with this example question and would like to see the workings as i assume I'm missing something obvious. My approach was to multiply by 1, find the value of a in terms of b, substitute that into the equation and then solve for b...

But in my answer box I'm not allowed variables so although I get to:

a=((5*13+sqrt(26)))/143)-b*sqrt(26)

That is not a valid answer because it can't contain b, but if I substitute that in place of a into the original formula and try to find b it all cancels each other out and I'm left with 0. So unless it's a trick and the answer is zero, I'm pretty lost.

Apologies for the horrendous text formula, this is just how I have to enter it on the site.