Find a formula for the nth term in this arithmetic sequence:
a1 = -7, a2 = -1, a3 = 5, a4 = 11, ...

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

Can (3,5 and square root 34) be sides on a right triangle?

The vertices of a triangle are a(7,5), b(4,2), c(9,2). what is m