def re ans1 , ans2 , af, bf
  [*0..9].repeated_permutation(2).to_a.each do |x,y|
    if af[x,y] == ans1
      if bf[x,y] == ans2
        print "x=",x , "_y=" , y
        print "_af_" ,  af[x,y] , "_"
        print "_bf_" ,  bf[x,y] , "\n"
        return x,y
      end
    end
  end
  nil
end

ans1 = 3
ans2 = 9
af = ->x,y{ x + y }        # x  + y  = 3
bf = ->x,y{ (x*2) + (5*y)} # 2x + 5y = 9

p re( ans1 , ans2 , af , bf)