If a1 =9 and an = -2an-1 then find the value of a4

Trevor and marissa together have 26 t-shirts to sell. if marissa has 6 fewer tshirts that trevor, find hiw many tshirts trevor has. identify the if-than moves in your solution

Brook states that the distance on the line is 4 units. caleb states that the whole line does not have a distance because it continues on forever. vivian states that the line is 6 units long. which distance did brook measure? which distance did vivian measure?

Let r = 3. what is the value of r + 58?