Find an equation for the nth term of the arithmetic sequence. -15, -6, 3, 12, ...

an = -15 + 9(n + 1)
an = -15 x 9(n - 1)
an = -15 + 9(n + 2)
an = -15 + 9(n - 1)

Another type of subtraction equation is 16-b=7. explain how you would sole this equation then solve it.

Asquare and an equilateral triangle have the same perimeter. each side the triangle is 4 inches longer than each side of the square. what is the perimeter of the square

Tan198=asin164=? how to solve this? ?