2sin^2x+2sin^2x*ctg^2x = 2sin^2x+2cos^2x = 2
p/(7a-14) +(7×1)/7(2-a)=(p-7)/(7a-14)
(c×13c)/c(bm-bn) -(b×12b)/b(cn-cm)=(13c^2+12b^2)/(cbm-cbn)
(4×a^2)/(4×5(a-b)) -(5×b^2)/(5×4(a-b))=(4a^2-5b^2)/20(a-b)
на фото..............