The sum of twice a number and 4 times the same number.
I need a algebraic expression to represent that.

Write the system of equations represented by the matrix. 0 1 2 4 -2 3 6 9 1 0 1 3

What is the volume of this square pyramid?

Jackie purchased 3 bottles of water and 2 cups of coffee for the family for $7.35. ryan bought 4 bottles of water and 1 cup of coffee for his family for 7.15. how much does each bottle of water cost? how much does each cup of coffee cost?