I need help with all 3 questions

For the following geometric sequence, find the recursive formula. {-80, 20, -5, } i need : ')

When keisha installed a fence along the 200 foot perimeter of her rectangular back yard, she left an opening for a gate.in the diagram below, she used x to represent the length in feet of the gate? what is the value? a. 10 b. 20 c. 25 d. 30

Rose bought a new hat when she was on vacation. the following formula describes the percent sales tax rose paid b=t-c/c