А) 12 - 7a >= 0
a <= 12/7; a ∈ (-oo; 12/7]<br>
б) 2 - x/3 < -4
x/3 > 6
x > 18; x ∈ (18; +oo)
в) (m-4)/7 - 1 >= -2
(m-4)/7 >= -1
m - 4 >= -7
m >= -3; m ∈ [-3; +oo)
г) 3 - 5y <= 2(7 - y)<br>3 - 5y <= 14 - 2y<br>-11 <= 3y<br>y >= -11/3; y ∈ [-11/3; +oo)
5) 3(x + 2) - 2(x - 1) >= 3x - 4
3x + 6 - 2x + 2 >= 3x - 4
x + 8 >= 3x - 4
12 >= 2x; x <= 6<br>Натуральных решений: 6, от 1 до 6.