21,34,67-кратные запишим так 21 -одного 42,63 ,84
−6(5−a)+3(−3a−3)−5(−8+a)
-30+6а-9а-9+40-5а=1+(-8а)
−15,26−(−34,74)−(+24,24)−(−4,77)+(−81,14)
-15,26+34,74-24,24+4,77-81,14=19,48-24,24+4,77-81,14=-4,76+4,77-81,14=0,01-81,14=-81,13
−22⋅(−x−y+z)=22х+22у-22z
А) = - 3,7 + (1 2/5 - (- 3/5) = - 3,7 + (1 2/5 + 3/5) = - 3,7 + 2 = - 1 ,7
б) = (- 1/14 +4/14) - (- 0,57 - 0,43) - 5/21 = 3/14 - (- 1) - 5/21 = 3/14 + 1 - 5/21 = 1 3/14 - 5/21 = 1 9/42 - 10/42 = 41/42
1)5000\5=1000
2)1000*7=7000
9 - ( 13/8 + 3/20 ) = 9 - ( 65+6 / 40 ) = 9 - 71/40 = 9/1 - 71/40 = 360-71 / 40 = 289/40 = 7 9/40
4 5/6 - ( 19/8 + 7/12 ) = 4 5/6 - ( 57+14 / 24 ) = 4 5/6 - 71/24 = 29/6 - 71/24 = 116-71 / 24 = 45/24 = 1 21/24 = 1 7/8