1)
8с+0,73=4,61-8с
8с + 8с = 4,61 - 0,73
16с = 3,88
c = 3,88:16
c = 0,2425
2)
13-(5х+11)=6х
13 - 5x - 11 = 6x
2 - 5x = 6x
6x + 5x = 2
11x = 2
x = 2:11
x = 2/11
3)
2=(3х-5)-(7-4х)
3x - 5 - 7 + 4x = 2
7x - 12 = 2
7x = 2 + 12
7x = 14
x = 14 : 7
x = 2
4)
8х+5=119+(7-3х)
8x + 5 = 119 + 7 - 3x
8x + 5 = 126 - 3x
8x + 3x = 126 - 5
11x = 121
x = 121 : 11
x = 11
5)
(4у+3)-(10у+11)=7+(13-4у)
4y + 3 - 10y - 11 = 7 + 13 - 4y
-6y - 8 = 20 - 4y
-6y + 4y = 20 + 8
-2y = 28
y = -28 : 2
y = -14
6)
(3-2х)+(4-3х)+(5-5х)=12+7х
3 - 2x + 4 - 3x + 5 - 5x = 12 + 7x
-10x + 12 = 12 + 7x
-10x - 7x = 12 - 12
-17x = 0
x = 0
7)
3у-(у-19)=2у
3y - y + 19 = 2y
2y + 19 = 2y
2y - 2y = -19
0 ≠ -19
уравнение не имеет корней