Find the $y$-intercept of the curve that passes through the point $(2,1)$ with the slope at $(x,y)$ of $\frac{-9}{{y}^{2}}$

$\frac{dy}{dx}=\frac{-9}{{y}^{2}}$

$\int {y}^{2}dy=\int -9dx$

$\frac{{y}^{3}}{3}=-9x+{C}_{1}$

${y}^{3}=-27x+C$ $(C=3{C}_{1})$

$y=(-27x+C{)}^{1/3}$

$1=(-27(2)+C{)}^{1/3}$

$C=54$

$0=(-27x+54{)}^{1/3}$

$y-intercept=(-2,0)$

Where is mistake?

$\frac{dy}{dx}=\frac{-9}{{y}^{2}}$

$\int {y}^{2}dy=\int -9dx$

$\frac{{y}^{3}}{3}=-9x+{C}_{1}$

${y}^{3}=-27x+C$ $(C=3{C}_{1})$

$y=(-27x+C{)}^{1/3}$

$1=(-27(2)+C{)}^{1/3}$

$C=54$

$0=(-27x+54{)}^{1/3}$

$y-intercept=(-2,0)$

Where is mistake?