Question.13. If A and B are focus of hyperbola 25[(x-1)^2+(y+1)^2]=k^2(3x+4y+5)^2,k>1 and P is a variable point on hyperbola such that triangle APB is right angled isosceles triangle. If K=tanα, α∈[0,2π] and sum of all values of α is (aπ/2b) (where a and b are co-prime numbers), then (7a+2b) is