What simple interest rate, to the nearest tenth, is needed for $15,000 to double in 8 years?

What are the sotions to the quadratic equation 9x^2=4

The measure of one angle of an octagon is two times smaller that of the other seven angles. what is the measure of each angle?

On #16 : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.