1: Ta có: \(\left(2x+3\right)\left(x-1\right)+\left(2x-3\right)\left(1-x\right)=0\)
\(\Leftrightarrow2x^2-2x+3x-3+2x-2x^2-3+3x=0\)
\(\Leftrightarrow6x=6\)
hay x=1
3: Ta có: \(x^2+3x-10=0\)
\(\Leftrightarrow\left(x+5\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-5\\x=2\end{matrix}\right.\)
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Câu 1:
1: Ta có: \(P=\left(x+4\right)^2+\left(x+5\right)\left(x-5\right)-2x\left(x+1\right)\)
\(=x^2+8x+16+x^2-25-2x^2-2x\)
\(=6x-9\)
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