При каком значении а верно равенство: а) а/5=6/15 б) 7/а=49/28 в) 13/2=78/а г) а/32=5/8 д) а/6=9/54 е) 1/12=4/а ж) 56/70=8/а

а) а/5 = 6/15;а /5 * 5 = 6/15 * 5;а = 30/15;а = 2.Проверка:2/5 = 6/15;2/5 = 2/5.б) 7/а = 49/28;7/а * а/7 = 49/28 * а/7;1 = а/4.1 * 4 = а/4 * 4;а = 4.Проверка:7/4 = 49/28;7/4 = 7/4.в) 13/2 = 78/а;13/2 * а/78 = 78/а * а/78;1/2 * а/6 = 1;а/12 = 1;а/12 * 12 = 1 * 12;а = 12.Проверка:13/2 = 78/12;13/2 = 13/2.г) а/32 = 5/8;а/32 * 32 = 5/8 * 32;а = 20.Проверка:20/32 = 5/8;5/8 = 5/8.д) а/6 = 9/54;а/6 * 6 = 9/54 * 6;а = 54/54;а = 1.Проверка:1/6 = 9/54;1/6 = 1/6.е) 1/12 = 4/а;1/12 * а/4 = 4/а * а/4;а/48 = 1:а/48 * 48 = 1 * 48;а = 48.Проверка:1/12 = 4/48;1/12 = 1/12.ж) 56/70 = 8/а;56/70 * а/8 = 8/а * а/8;а/10 = 1;а/10 * 10 = 1 * 10;а = 10.Проверка:56/70 = 8/10;4/5 = 4/5.з) 6/5 = а/60;6/5 * 60 = а/60 * 60;а = 72.Проверка:6/5 = 72/60;6/5 = 6/5.