$400 interest is earned on a principal of $2,000 at a simple interest rate of 59 interest per year. For how many years was the principal invested?​

Ametalworker has a metal alloy that is 30? % copper and another alloy that is 55? % copper. how many kilograms of each alloy should the metalworker combine to create 90 kg of a 50? % copper? alloy?

Find the equation using the point (4,8)

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180