Ответ: (3;-2)
1) 8x + 5,9 = 7x + 20
8x - 7x = 20 - 5,9
-x = 14,1
x = -14,1
2) -2x + 16 = 5x - 19
-2x - 5x = -16 - 19
-7x = -35
x = 5
3) -2/5x + 3/5 = 1/5x
-2/5x - 1/5x = -3/5
-3/5x = -3/5
x = 1
4) 2/3z = 2/9z - 4/9
6/9z - 2/9z = -4/9
4/9z = -4/9
z = -1
5) 1,3x - 11 = 0,8x +5
1,3x - 0,8x = 5 + 11
0,5x = 16
x = 32
6) -4 (-x + 7) = x + 17
4x - 28 = x + 17
4x - x = 17 + 28
3x = 45
x = 15
7) c - 32 = -7 (c + 8)
c - 38 = -7c - 56
c + 7c = -56 + 38
8c = 18
c = 2,25
f(- 5) = 1
f(- 3,5) = 2,5
f(- 2) = 4
f(1,5) = 3,5
f(3) = 3