Ответ(ы) на вопрос:
Гость№193.
8(6а-7) - 17а = 48а - 56 -17а = 31а - 56
6b - 7(12-3b) = 6b - 84 + 21b = 27b -84
1.6(c-8) - 0.4(8-3c) = 1.6c - 12.8 - 3.2 + 1.2c = 2.8c -16
1.6(9a -3b)-(4b -6a)*1.5 = 14.4a -4.8b - 6b + 9a= 23.4a - 10.8b
-(5.7m -6.7) - (7.9 -3.6m) = - 5.7m +6.7 -7.9 +3.6m = -2,1m - 1,2
15/16 * (5 1/3 * x - 4/15 * y ) - 7/23 * (3 2/7 * x - 2 4/21 * y ) =
= (15/16) * (16/3)* x - (15/16) * (4/15)*y - (7/23)*(23/7)* x + (7/23)*(46/21)*y=
= (15/3) * x - (4/16)*y - 1*x + (2/3)*y =
= (5x -x) + ( (- 1/4 ) * y + (2/3 ) * y =
= 4x + y * ( - 3/12 + 8/12) =
= 4x + (5/12) * y
№ 194.
17x - (2x +5y) = 17x -2x -5y = 15x -5y = 5*(3x -y)
при 3х -у = -0,8 ⇒ 5 * (-0,8) = -4,0 = - 4
№195.
0,8(3а-13) -0,6(а-8) = 2,4а -10,4 -0,6а +4,8= 1,8а -5,6
при а = - 3 1/12
1,8 * (- 3 1/12 ) - 5,6 = 9/5 * (- 37/12) - 5,6 =
= - 111/20 - 5,6 = - 5,55 - 5,6 = - (5,55 + 5,60 ) =
= - 11,15
6 5/9 * (n - 9) + 2 2/9 * (18 - n) =
= 6 5/9 * n - (59/9) * (9/1) + (20/9) * (18/1) - 2 2/9 * n =
= n * ( 6 5/9 - 2 2/9 ) - 59 + 40 =
= 4 1/3 * n - 19
при n=0.3
4 1/3 * 0.3 - 19 = 13/3 * 3/10 - 19 =
= 13/10 - 19 = 1.3 - 19 = - 17.7
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