8/15•(2 1/4х-7 1/2у)-7/30•(4 2/7х-8 4/7у)
СРОЧНО!

8/15×(2 1/4х-7 1/2у)-7/30×(4 2/7х-8 4/7у)==8/15×2 1/4х-8/15×7 1/2у-7/30×4 2/7х+7/30×8 4/7у==2/5×3/1х-4/1×1/1у-1/1×1/1х+1/1×2/1у=6/5х-4/1у-1/1х+2/1у==1 1/5х-4у-1х+2у=1 1/5х-1х-4у+2у=1/5х-2у