Find an explicit formula for the following sequence, an, which starts with a1=7.
7,21,63,189,567,…

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"

Grace is standing 18 feet from a lighthouse and kelly is standing 10 feet from grace. the angle that grace looks up to see the top of the lighthouse is 45°. the angle that kelly looks up to see the top of the lighthouse is y°. find the height, h, of the lighthouse. find the angle, rounded to the nearest tenth of a degree, in which kelly looks up to the top of the lighthouse. to the nearest tenth of a degree, find the value of x° . in two or more sentences, explain your calculations

The area of each triangle is 7 square units. the surface area of the triangular prism is