а) = (a-2b)² × y/(a-2b)(a+2b) = (a-2b)×y/a+2b = ay-2by/a+2b
b) ...= (2a-1)(2a+1)/a-3 × 1/3(2a+1) = 2a-1/a-3 × 1/3 = 2a-1/3(a-3) = 2a-1/3a-9
а) = (a-2b)² × y/(a-2b)(a+2b) = (a-2b)×y/a+2b = ay-2by/a+2b
b) ...= (2a-1)(2a+1)/a-3 × 1/3(2a+1) = 2a-1/a-3 × 1/3 = 2a-1/3(a-3) = 2a-1/3a-9