1) -6+3x>=2.1+0.9x
2.1x>=8.1
x>= 8.1/2.1
2) a-b = 12
1/4a+3/4b=31
a=12-b => (12-b)*1/4+3/4=31 => 3-1/4b+3/4b = 31 => 2/4b=29 => b = 58
a = 12-58 = -46
Объяснение:
1) -6+3x>=2.1+0.9x
2.1x>=8.1
x>= 8.1/2.1
2) a-b = 12
1/4a+3/4b=31
a=12-b => (12-b)*1/4+3/4=31 => 3-1/4b+3/4b = 31 => 2/4b=29 => b = 58
a = 12-58 = -46
Объяснение: