2/3 ( 6-9х)=15 3/4 (12-х)=3/2 2/5 ( 8-5х)=1/5
2/3 ( 6-9х)=15 6-9x=15цел.3/2 -9x+6=15×3/2 -9x+6=45/2 -9x=45-12/2 -9х+6-6=45/2-6 х=(45-12)×1/-2×9 x=33/-18 х=11/-6