The angle of 2 is 150 degrees
Factor the equation so...
(r^2-pr) and (p^2q-pqr)
Factor out (r^2-pr) = r(r-p)
Factor out (p^2q-pqr) = pq(p-r)
Add a negative to r(r-p) to make it -r(p-r)
(pq-r)(p-r) is the answer... I'm sorry I can't explain things well, but I tried.
The answer is HL. HL is a theorem stating that if the hypotenuse and one leg are congruent to another pair of hypotenuse and leg then the triangles themselves are congruent. Hope this helps.
