Упростите выражение: а) 16/(x−4) − x²/(x−4); б) 25/(a+5) − a²/(a+5); в) (3a−1)/(a²−b²) − (3b−1)/(a²−b²); г) (x−3)/(x²−64) + 11/(x²−64); д) (2a+b)/(a−b)² + (2b−5a)/(a−b)²; е) (13x+6y)/(x+y)² − (11x+4y)/(x+y)².

а) \(\dfrac{16-x^2}{x-4}=\dfrac{(4-x)(4+x)}{x-4}=-(x+4)\).

б) \(\dfrac{25-a^2}{a+5}=\dfrac{(5-a)(5+a)}{a+5}=5-a\).

в) \(\dfrac{3a-1-(3b-1)}{a^2-b^2}=\dfrac{3(a-b)}{(a-b)(a+b)}=\dfrac{3}{a+b}\).

г) \(\dfrac{x-3+11}{x^2-64}=\dfrac{x+8}{(x-8)(x+8)}=\dfrac{1}{x-8}\).

д) \(\dfrac{2a+b+2b-5a}{(a-b)^2}=\dfrac{3(b-a)}{(a-b)^2}=-\dfrac{3}{a-b}\).

е) \(\dfrac{13x+6y-11x-4y}{(x+y)^2}=\dfrac{2x+2y}{(x+y)^2}=\dfrac{2}{x+y}\).