(x-7)-(2x+9)=-13
раскроем скобки
x-7-2x-9 = -13
-x-3 = 0
x+3 = 0
x = -3
0,6+(0,5y-1)=y+0,5
0.6+0.5y-1 = y+0.5
-0.5y-0.9 = 0
0.5y+0.9 = 0
0.5y = -0.9
y = -1.8
(x-7)-(2x+9)=-13
раскроем скобки
x-7-2x-9 = -13
-x-3 = 0
x+3 = 0
x = -3
0,6+(0,5y-1)=y+0,5
раскроем скобки
0.6+0.5y-1 = y+0.5
-0.5y-0.9 = 0
0.5y+0.9 = 0
0.5y = -0.9
y = -1.8