I believe it's 2x by 3x (gets you 6x^2) + 5x + 6 (gets you 11x) then you take 5 by 5 which gives you 10.
I might be a tad rusty since I haven't done this since 8th grade - BUT, I believe this is the way you do it. There's an easier way with multiples but I don't believe it works here since you can't accurately double 2 to get 6.
