Сделайте №1(а),№2(а),№3(б,в,г)

1. а) ОДЗ 5у-1=0 5у=1 у=1/5=0,2 3у+9=0 3у=-9 у=-9/3 у=-3 2. а) [latex] \frac{0,6*5mn- m^{2}-3mn }{5n} = \frac{3mn- m^{2}-3mn }{5n} = \frac{ m^{2} }{5n} = \frac{(-4)^{2} }{5*0.8}= \frac{16}{4}=4 [/latex] 3. б)[latex] \frac{4c+3d}{(-1) ^{2}(4c+3d)^{2} }= \frac{1}{4c+3d} [/latex] в)[latex] \frac{(5a+2b) ^{2} }{(-1) ^{2}(5a+2b)^{2} }=1 [/latex] г) [latex] \frac{3(a-2b)}{-a(a-2b)-c(a-2b)} = \frac{3(a-2b)}{(-a-c)(a-2b)}= \frac{3}{-a-c}=- \frac{3}{a+c} [/latex]