1.
х-5(х-4)≥9х-(5-2х)
х-5х+20≥9х-5+2х
-4х-11х≥-5-20
-15х≥-25
х≤25/15
х≤50/30
1,87 : 1,1 + 1/3 = 1,7 + 1/3= 17/10 + 1/3 = (17*3+10)/30=61/30=2 ¹/₃₀
2,9+0,4*(-3 ¹/3)=2,9+0,4*(-10/3)=2,9 - (4/10)*(10/3)=29 - 4 = 29*3-4*10 =
10 3 30
=87-40 =47 = 1 ¹⁷/₃₀
30 30
Ответ: 1 ¹⁷/₃₀
2) {6x-3(x-1)≥2+5x
{5(x-1)+8≥1-3(x+2)
6x-3(x-1)≥2+5x
6x-3x+3≥2+5x
-2x≥-1
x≤0.5
5(x-1)+8≥1-3(x+2)
5x-5+8≥1-3x-6
8x≥-8
x≥-1
{x≤0.5
{x≥-1
\\\\\\\\\\\\\\\\\\\\\\\\\\\
---------- -1 ------------ 0.5 ----------
\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
-1≤x≤0.5
x∈[-1; 0,5]