1. 4+8y +8 = 2y - 10 - 7y +9
12 + 8y = -5y - 1
8y + 5y = -1 -12
13y = -13
y = -13 / 13
y = -1
2. 3x/5 = 6+x/3
9x = 30 + 5x
9x - 5x = 30
4x = 30
x = 30/4
x = 7,5
3. 8x - (7x + 8) = 9
8x - 7x - 8 = 9
8x - 7x = 9 + 8
x = 17
Х(х-10)>0
х=0
х=10
___+___0___-____10_____+___
(-&;0)(10;+&)