5 7/15х-1 11/12х+16 9/20=5 28/60х-1 55/60х+16 9/20=
=4 88/60х-1 55/60х+16 9/20=3 33/60х+16 9/20=3 11/20х+16 9/20
при х= 3 7/71
3 11/20×3 7/71+16 9/20=27 9/20 или 27,45
1)3 11/20×3 7/71=71/20×220/71=1/1×11/1=11
2)11+16 9/20=27 9/20 (27 9/20=27 45/100=27,45)