Simplify by adding like terms -7x-9x+4-6y-3x+5-3y

Asocial networking site currently has 400,000 active members, and that figure is predicted to increase by 32% each year. the following expression represents the number of active members on the site after t years.

Solve the equation by completing the square. x^2+2x=17

Angles r and s are complementary. the measure of angle r is 31 degrees. which equation can be used to find angle s?