Вправи 801- 887 » 828

828. Скороти дріб. a) (√a-1)/(a-1) = (√a-1)/((√a-1)(√a+1)) = 1/(√a+1); б) (√x-√z )/(x- z) = (√x-√z )/((√x-√z)(√x+ √z) ) = 1/(√x+√z ); в) (a+ √2)/(a^2-2) = (a+√2 )/((a-√2)(a+√2) ) = 1/(a-√2 ). г) (√a+1)/(√a+ a) = (√a+1)/(√a(1+√a) ) = 1/√a; ґ) (√a+√x )/(a√a+ x√a) = (√a+ √x)/(√ax(√a+√x) ) = 1/√ax; д) (a+2√a+1)/(a-1) = 〖(√a+1)〗^2/((√a-1)(√a+1)) = (√a+1)/(√a-1). е) (x-6√x+9)/(x-9) = 〖(√x-3)〗^2/((√x-3)(√x+3)) = (√x-3)/(√x+3); є) 〖(√3+1)〗^2/(2+ √3) = (3+2√3+1)/(2+ √3) = (4+2√3)/(2+√3 ) = (2(2+ √3))/(2+ √3) = 2; ж) 〖(√7-1)〗^2/(√7-4) = (7-2√7+1)/(√7-4) = (8-2√7)/(√7-4) = (-2(√7-4))/(√7-4) = –2.