1) 12*18 + 4 = 216 + 4 = 220
2) 48 : (20-4) = 48 : 16 = 3
3) (14 - 6) * (13 + 6) = 8*19 = 152
4) 6*7 - 63:9 = 42 - 7 = 35
5) (12 - 4) * (24 : 6) = 8 * 4 = 32
1)a3=8,d=3,a1-?2) a1=10, d=4, n=113)a3=25, a10=-3,a1-?, d-?4)a1=3, a2=7, a51-?5)a11=23, a21=43,a51-?6)a1=-5,d=4,S18-?
Nastya91
1) a1=a3-2d=8-6=2
2) a11=a1+10d=10+40=50
3) d=(a10-a3)/7=(-3-25)/7=-4. a1=a3-2d=25-(-8)=33
4)d=a2-a1=7-3=4, a51=a1+50d=3+50*4=253
5) d=(a21-a11)/10=(43-23)/10=2. a51=a21+30d=43+60=103
6) S18=(a1+a18)/2*18. a18=a1+17d=-5+17*4=63. S18=(-5+63)/2*18=522
360 - НОД (45,72)
216 - НОД (54,72)
2 : (-3/5) : 2 - 3/2 : 6 + 6 : 3/2=-2*5/3*1/2-3/2*1/6+6*2/3=-5/3-1/4+4=
=-20/12-3/12+4=-23/12+4=-1 11/12+4=2 1/12
(2/15 + 19/12) * 30/103 - (1 : 9/4) * (-9/16)=(8/60 + 95/60) * 30/103 + 1*4/9*9/16=
=103/60*30/103+1/4=1/2+1/4=2/4+1/4=3/4=0,75