Solve the system by the addition method.
3x + 15y = 6
4x - 15y = 8

Louis wants to carpet the rectangular floor of his basement.the basement has an area of 864 square feet.the width of the basement is 2/3 it's length. what is the length of louis's basement

What is the area of the original rectangle? 8 cm² 20 cm² 25 cm² 40 cm²

Aculinary club earns $1360 from a dinner service. they sold 45 adult meals and 80 student meals. an adult meal costs twice as much as a student meal. what is the cost of an adult meal?