a)11x-7<8x+7
<-->11x-8x<7+7
<-->3x<14
<--->x<14/3 mà x nguyên dương
---->x \(\in\){0;1;2;3;4}
b)x^2+2x+8/2-x^2-x+1>x^2-x+1/3-x+1/4
<-->6x^2+12x+48-2x^2+2x-2>4x^2-4x+4-3x-3(bo mau)
<--->6x^2+12x-2x^2+2x-4x^2+4x+3x>4-3+2-48
<--->21x>-45
--->x>-45/21=-15/7 mà x nguyên âm
----->x \(\in\){-1;-2}
c)2(3-x)-1,5(x-4)<3-x
<--->6-2x-1,5x+6<3-x
<--->6+6-3<2x+1,5x-x
<--->9<2,5x
<--->3,6<x mà x la so nguyen nhỏ nhất
--->x=4
b ) \(\frac{x^2+2x+8}{2}-\frac{x^2-x+1}{6}>\frac{x^2+x+1}{3}-\frac{x+1}{4}\)
\(\Rightarrow6\left(x^2+2x+8\right)-2\left(x^2+x-1\right)>4\left(x^2+x+1\right)-3\left(x-1\right)\)
(bỏ mẫu phải đổi dấu)
\(\Leftrightarrow6x^2+12x+48-2x^2-2x+2>4x^2+4x+4-3x+3\)
\(\Leftrightarrow4x^2+10x+50>4x^2+x+7\)
\(\Leftrightarrow4x^2+10x-x>7-50\)