Need help will mark Brainliest no experience needed

Which equation represents the partial sum of the geometric series?

Me! i really need to get this right before 9. prove the divisibility of 7^6+7^5-7^4 by 11. use factoring so you get a number times 11. just tell me the number. i need this done asap

What is perpendicular to y=-1/2x+11