Bài 1:
a: Ta có: 0x<-3
nên \(x\in\varnothing\)
b: Ta có: \(\dfrac{4x+1}{4}-\dfrac{5x+2}{6}< \dfrac{x+1}{3}\)
\(\Leftrightarrow12x+3-10x-4< 4x+4\)
\(\Leftrightarrow2x-1-4x-4< 0\)
\(\Leftrightarrow-2x< 5\)
hay \(x>-\dfrac{5}{2}\)
c: Ta có: \(\dfrac{3x-1}{5}+\dfrac{x-13}{2}>\dfrac{7x}{3}-\dfrac{11\left(x+3\right)}{2}\)
\(\Leftrightarrow18x-6+15x-195>70x-165\left(x+3\right)\)
\(\Leftrightarrow33x-201>70x-165x-495\)
\(\Leftrightarrow128x>-294\)
hay \(x>-\dfrac{147}{64}\)
Bài 2:
a: Ta có: (x+4)(x-5)>0
\(\Leftrightarrow\left[{}\begin{matrix}x-5>0\\x+4< 0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x>5\\x< -4\end{matrix}\right.\)
b: Ta có: \(x^2+x-12< 0\)
\(\Leftrightarrow\left(x+4\right)\left(x-3\right)< 0\)
\(\Leftrightarrow-4< x< 3\)
