Explain me how to solve it
cos2x+cos4x ≥0

For what values of x is x2 + 2x = 24 true?

Money off coupons have been circulated to 300 households. only 2/5 of these were redeemed (used) in the local supermarket to get a free shampoo. what fraction of coupons were unused? (ps: write how you got the answer)

Javier bought a painting for $150. each year, the painting's value increases by a factor of 1.15. which expression gives the painting's value after 77 years?