\(x^2 +5x+1=\left(x+5\right)\sqrt{x^3+1}\)

\(\left\{{}\begin{matrix}x^3-y^3-15y-14=3\left(2y^2-x\right)\\4x^3+6xy+15x+3=0\end{matrix}\right.\)

\(\left\{{}\begin{matrix}x^3-y^3-15y-14=3\left(2y^2-x\right)\\4x^3+6xy+15x+3=0\end{matrix}\right.^{ }}\)

\(\frac{x^3}{\sqrt{5-x^2}}+8x^2=40\)

\(\left\{{}\begin{matrix}x\left(x+y\right)+y^2-4y+1=0\\y\left(x+y\right)^2-2x^2-7y=2\end{matrix}\right.\)