Y - ( 2/9 ) y = 4 ( 2/3 ) ;
( 7/9 ) y = 14/3 ;
( 7/9 ) y = 42/9 ;
7y = 42 ;
Y = 42 : 7 ;
Y = 6
59-50=9(цена одной ручки)
50-9=41(цена пенала)
<span>(3sint+4cost)²+(4sint-3cost)²=9sin</span>²t+16cos²t+24sintcost + 16sin²t+9cos²t-24sintcost = 25sin²t+25cos²t = 25