Find the roots of the quadratic polynomial $ \mathrm{t}^{2}-15 $.

$h(t) = t^2 – 15$

Here, we have to find the roots of h(t). 

To find the zeros of h(t), we have to put $h(t)=0$.

This implies,

$t^2 – 15 = 0$

$t^2 – \sqrt{(15)^2} = 0$

$(t+\sqrt{15})(t-\sqrt{15})= 0$  (since $a^2-b^2=(a+b) (a-b) $) 

$t+\sqrt{15}=0$ and $t-\sqrt{15}=0$

$t=-\sqrt{15}$ and $t= \sqrt{15}$

Therefore, the zeros of the quadratic equation $h(t) = t^2 – 15 $ are $-\sqrt{15}$ and $\sqrt{15}$.