1. 32/5 * 25/16 - 81/16= 2*5-81/16=10-81/16= 160-81/16=79/16=4 15/16
2. 15* 15+5-3/15= 15* 17/15 = 17
0,3*(51/14-31/21+7/6) = 3/10 * 153-62+49/42 = 3/10 * 140/42 = 14/14 = 1
3. 11 5 4 66с-25с-36с 5с с
--- с - --- с - -----с= --------------------- = ------= ------
15 18 10 90 90 18
0,5х+1/7х+7,4-9/14х = (7х+2х-9х)/14 + 37/5 = 0/14 + 37/5 = 0+37/5=37/5 = 7 2/5