№ 440.
1) ( - 2 3/4 + 0,7) + 1,35 = (- 2 3/4 + 7/10) + 1 35/100 = (- 2 15/20 + 14/20) + 1 35/100 = ( - 55/20 + 14/20) + 135/100 = - 41/20 + 135/100 = - 205/100 + 135/100 = - 70/100 = - 0,7
2) (8,6 + (-5,9)) + (- 2 7/10) = 2,7 + (- 2,7) = 0
№ 445
Х - 2,76 = - 4
Х = - 4 + 2,76
х = - 1,24
х - 8 1/4 = - 3,2
х = - 3,2 + 8 1/4
х = - 3 2/10 + 8 1/4
х = - 32/10 + 33/4 = - 64/20 + 165/20
х = 101/20 = 5,05
у - 2 7/9 = - 8
у = - 8 + 2 7/9
х = - 8 + 25/9
х = - 72/9 + 25/9
х = - 47/9 = - 5 2/9