原式=(√a-√b)²/(√a-√b)(√a+√b)+[√a/√a(√a+√b)+√b/√b(√a-√b)]×√b
=(√a-√b)²/(a-b)+[1/(√a+√b)+1/(√a-√b)]×√b
=(√a-√b)²/(a-b)+[(√a+√b)+(√a-√b)]/(√a+√b)(√a-√b)×√b
=(a-2√ab+b)/(a-b)+2√(ab)/(a-b)
=(a+b)/(a-b)