For $\mathrm{t}>-1$, let $\alpha_{\mathrm{t}}$ and $\beta$, be the roots of the equation $$ \left((t+2)^{1 / 7}-1\right) x^2+\left((t+2)^{1 / 0}-1\right) x+\left((t+2)^{2 / 2}-1\right)=0 \text {. If } \lim _{t \rightarrow-1} \alpha_t=a \text { and } \lim _{t \rightarrow-1} \beta_t=b $$ then $72(a+b)^2$ is equal to $\_\_\_\_$ in