\(a,\left(x-1\right)\left(x+3\right)-x^2+9>0\\ \Leftrightarrow x^2+2x-3-x^2+9>0\\ \Leftrightarrow2x>-6\\ \Leftrightarrow x>-3\)

\(b,\dfrac{x+2}{3}-\dfrac{3x-1}{5}< -2\\ \Leftrightarrow\dfrac{5\left(x+2\right)-3\left(3x-1\right)}{15}< -2\\ \Leftrightarrow5x+10-9x+3< -30\\ \Leftrightarrow-4x< -43\\ \Leftrightarrow x>\dfrac{43}{4}\)

\(a,\left(x-3\right)\left(x+3\right)-x\left(x+2\right)\le0\\ x^2-9-x^2-2x\le0\\ \Leftrightarrow-2x\le9\\ \Leftrightarrow x\ge-\dfrac{9}{2}\)

\(b,\dfrac{x-1}{4}-1>\dfrac{x+1}{3}+8\\ \Leftrightarrow\dfrac{3\left(x-1\right)-12-4\left(x+1\right)-8.12}{12}>0\\ \Leftrightarrow3x-3-12-4x-4-96>0\)

\(\Leftrightarrow-x>115\\ \Leftrightarrow x< -115\)

3. PHONG THANH đúng không anh =)?

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