If O is an angle in standard position and its terminal side passes through the point (15,8), find the exact value of sec 0 in simplest radical form.

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?

Solve 3x-18=2y and 5x-6y=6 by elimination show work

Evaluate the discriminant of each equation. tell how many solutions each equation has and whether the solutions are real or imaginary. x^2 - 4x - 5 = 0