Question

Answer 1

\(\Leftrightarrow\)\(2\left(x+1\right)^2=21-3y^2\le21\)

\(\Leftrightarrow\left(x+1\right)^2\le\dfrac{21}{2}\)

TH1: \(x+1=0\Rightarrow y^2=7\left(L\right)\)

TH2: \(x+1=\pm1\) \(\Rightarrow y^2=\dfrac{19}{3}\left(L\right)\)

TH3:\(x+1=\pm2\)\(\Rightarrow y^2=\dfrac{13}{3}\left(L\right)\)

TH4: \(x+1=\pm3\)\(\Rightarrow y^2=1\Rightarrow y=\pm1\)

Vậy các nghiệm \(\left(2;1\right),\left(2;-1\right);\left(-2;1\right),\left(-2;-1\right)\)