Giao lưu:
(1)+(2)\(4x^2+2x=12\Leftrightarrow z^2+z-12=0\Rightarrow\orbr{\begin{cases}z=-4\Rightarrow x=-2\\z=3\Rightarrow x=\frac{3}{2}\end{cases}}\\ \)
thế vào (2) \(\orbr{\begin{cases}y^2=\frac{5}{2}-4\left(loai\right)\\y^2=\frac{5}{2}-\frac{9}{4}=\frac{1}{4}\Rightarrow=+-\frac{1}{2}\end{cases}}\)