Вправа 201 - 300 » 229

229. Виконай множення. a) 〖(x- y)〗^2/((x+ y)y) • y^2/(x^2-y^2 ) = (〖(x- y)〗^2•y^2 )/(y(x+ y)(x- y)(x+ y)) = (y(x- y))/〖(x+ y)〗^2 ; б) (a^2-4)/(a^2+4) • (a+2)/(a-2) = ((a-2)(a+2)(a+2))/(〖(a〗^2+4)(a-2)) = 〖(a+2)〗^2/(a^2+4); в) (x^2-1)/(x^3-1) • (x^2+ x+1)/(x+1) = ((x-1)(x+1)(x^2+ x+1))/((x-1)(x^2+ x+1)(x+1)) = 1.