Answer:
y=x\\
x=y^{2} + 12y\\
y^{2} + 12y -x = 0\\
Delta = (12^{2}) - 4.1.(-x) = 144 +4X = 36.(4+x)
\sqrt{Delta} = 6 . \sqrt{(4+x)} \\
y' = \frac{-12 + 6.(\sqrt{(4+x)}}{2} = -6 + 3.\sqrt{(4+x)}\\
y" = -6 - 3.\sqrt{(4+x)}\\\\
y' = 3.\sqrt{(4+x)} - 6\\
y''= -3.\sqrt{(4+x)} - 6\\
