Show that every finite spanning set for $\displaystyle \mathbb{R}^d$ is a frame for $\displaystyle \mathbb{R}^d$

(frame:$\displaystyle \exists A,B >0 \in such that A ||x||^2<=\sum|<x,f_k>|^2<=B||x||^2$ )

and that every finite frame $\displaystyle {f_1,\ldots,f_n}\subset \mathbb{R}^d, n>d $ is a spanning set for $\displaystyle \mathbb{R}^d$