$[-/3$ Points$]$

$$ SCALCET$9$M $10\mathrm{.}2\mathrm{.}015.$

Find $\frac{dy}{dx}$ and $\frac{d^{2}y}{d{x}^2}.$

$x=t^2+2,y=t^2+7t$

$\frac{dy}{dx}=$

$\frac{d^{2}y}{d{x}^2}=$

Find the values of t for which the graph described by the parametric equations is concave up$.($Enter your answer using interval notation.$)$

$$