A brick weighs w kg. Write an expression for the weight of 12 bricks.

Which ordered pair (c, d) is a solution to the given system of linear equations- c+2d=13 -9c-4d=-15

The perimeter of a movie screen is 54 meters. the screen is 18 meters wide. how tall is it?

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?