\(x^2-3y^2-2xy+10x+14y-18\)
\(=x^2-2xy+y^2-2x^2+10x-4y^2+14y-18\)
\(=x^2-2xy+y^2-2\left(x^2-5x+25\right)-4\left(y^2-\frac{7}{2}y+\frac{49}{16}\right)+\frac{177}{4}\)
\(=\left(x-y\right)^2-2\left(x-5\right)^2-4\left(y-\frac{7}{4}\right)^2+\frac{177}{4}\)
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