А) х-8=2:2/5
х-8=2*5/2
х-8=5
х=5+8
х=13
б) 7/3х=7/3+7/3
7/3х=14/3
х=14/3:7/3
х=14/3*3/7
х=2
(-5*5/45 + 14*3/45):(17/30)= (-25/45+42/45)*(30/17)= (17/45)*(30/17)= 30/45= 2/3
2/3x-7=11
2/3x=11+7=18
x=(18 3)/2=27
3/5x-6=3
3/5x=3+6=9
x=(9 5)/3=15
2 1/2y+5 1/2y-2=3
2 1/2y+5 1/2=3+2=5
5/2y+11/2y=5
16/2y=5
8y=5
y=5/8