y equals the # of hours u practiced so u substitute y for the # of hours and then solve for x. if im right u multiply x times 7 and u get how many minutes per week u practice the new song. and just the x represents what u practice in a day 210=7(15+x) 210/7=15+x 30-15=x 15 min =x 245=7(15+x) 245/7=15+x 35-15=x 20=x 315=7(15+x) 315/7=15+x 45-15=x 30 min=x