4х+4х=424 8х=424 х=424/8 х=53 15у-8у=714 7у=714 у=714/7 у=102 9z+z=500 10z=500 z=500/10 z=50 10k-k=702 9k=702 k=702/9 k=78 4l+5l+l=1200 10l=1200 l=1200/10 l=120 6t+3t-t=6400 8t=6400 t=6400/8 t=800
А)4х+4х=424 8х=424 х=424:8 х=53
А можно все остальные?