formula that we have to use: a_n=ar^n-1

if we plug it in we get: 1=ar^0

4096=ar^6

If we divide the 2nd equation by the first equation all we get is 4096=r^6..... now the answer is +-4....... so am I suppose to know off the top of my head that 4096 is 4^6..... so then... 4^6=r^6...... square root both sides by 6........ r=+-4......

There must be a simpler way to do this.