a: \(Q=\dfrac{15\sqrt{x}-11-3x-9\sqrt{x}+2\sqrt{x}+6-2x+2\sqrt{x}-3\sqrt{x}+3}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-1\right)}\)
\(=\dfrac{-5x+7\sqrt{x}-2}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-1\right)}=\dfrac{-5\sqrt{x}+1}{\sqrt{x}+3}\)
b: Khi x=(căn 17-3)^2 thì \(Q=\dfrac{-5\sqrt{17}+15+1}{\sqrt{17}}=\dfrac{-5\sqrt{17}+16}{\sqrt{17}}\)
c: Q=-1/7
=>\(\dfrac{5\sqrt{x}-1}{\sqrt{x}+3}=\dfrac{1}{7}\)
=>35*căn x-7=căn x+3
=>34căn x=10
=>căn x=5/17
=>x=25/289
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