1) x+2>=15 ; x>=15-2 x>=13 2) 3<=z-6 z>=6-3 z>= 3 3) 2a>=a-7 2a-a>=7 1a>=7 a>=7 4) 12x>= -36 x>= -36/12 x>= -3 5) y/4 <= x+5 y-x<=5*4 y-x<=20 y<=20*4 y<=80 x>=20-5 x>=15 Ответ y<=80 x >=15 6) 3(x+1)<=x+15 3x+3<=x+15 3x-x<=15-3 2x<=12 x<=12/2 x<=6 7) 2(x+3)+4< x-2 2x+6+4<x-2 2x-x< -2-6-4 x< -12