a: \(M=\dfrac{x}{x-3}:\left(\dfrac{x-2\left(x-3\right)}{x\left(x-3\right)}\right)\)
\(=\dfrac{x}{x-3}\cdot\dfrac{x\cdot\left(x-3\right)}{x-2x+6}=\dfrac{x^2}{-x+6}\)
b: \(\dfrac{3}{x-5}-\dfrac{2}{x+5}=\dfrac{-29}{25-x^2}=\dfrac{29}{x^2-25}\)
=>3x+15-2x+10=29
=>x=4
Khi x=4 thì \(M=\dfrac{4^2}{-4+6}=\dfrac{16}{2}=8\)
c: \(P=\dfrac{x^2}{-x+6}+\dfrac{x+6}{2}\)
\(=\dfrac{-x^2}{x-6}+\dfrac{x+6}{2}=\dfrac{-2x^2+x^2-36}{2\left(x-6\right)}=\dfrac{-x^2-36}{2\left(x-6\right)}\)
P=5
=>-x^2-36=10x-30
=>-x^2-10x-26=0
=>\(x\in\varnothing\)
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