Question

100 баллов, желательно быстрее

Answer 1

$\cfrac{5}{dx-dy}+\frac{4}{by-bx}=\cfrac{5(by-bx)+4(dx-dy)}{(dx-dy)(by-bx)}=\cfrac{5b(y-x)+4d(x-y)}{db(x-y)(y-x)}=$

$=\cfrac{-5b(x-y)+4d(x-y)}{db(x-y)(y-x)}=\cfrac{(x-y)(-5b+4d)}{db(x-y)(y-x)}=\cfrac{-5b+4d}{db(y-x)}$