найдите корень уравнения 2) y - y/7 = 5 1/7 3) y - 1/y = 8 8/9 4) y + 3/y = 10 3/10

2) y-y/7=5*1/7

y-y/7=36/7 |*7

7y-y=36

6y=36

y=6

3) y-1/y=8*8/9

y-1/y=80/9 |*9y

9y^2-9=80y

9y^2-80y-9=0

D = (-80) ^2+9*9*4=6724

x1 = (80+82) / 18=9

x2 = (80-82) / 18=1/9

4) y+3/y=10*3/10

y+3/y=103/10 |*10y

10y^2+30=103y

10y^2+30-103y=0

10y^2-103y+30=0

D = (-103) ^2-30*10*4=10609-1200=9409

x1 = (103+97) / 20=10

x2 = (103-97) / 20=6/20=3/10=0,3