<span>а)х*(у*5)=(x*y)*5=12*5=60
б)(х*2)*у=(x*y)*2=12*2=24
в)у*(х*10)=(x*y)*10=120
г)(у*2)*(х*3)=(x*y)*2*3=12*6=72</span>
1) 3×(48+23)=213
2) 2×(53-19)=68
3) 735:(85-36)=15
4)(251+649) : 75=12
25 человек- 100%
х=(12*100)/25=48%
1) =1/5*4/9*1/3=4/15+1/3=4+5/15=9/15=3/5=0.6
2)=1/2*1/5-1/3=1/10-1/3=3-10/30=-7/30
3)=3/8*2+3/4=3/4+3/4=3+3/4=6/4=3/2=1,5
4)=2/5*7/5+3/8=14/25+3/8=112+75/200=187/200=0,935