The first four problems deal with the area of the rectangle, or length times width(7*3,m*m=m^2).
The last four problems are dealing with adding areas. Find the area of the two rectangles(length times width), then add them together to find the total area.
They are asking for an expression. An expression is made up of terms, variables, and an operation. They do not contain equal signs.
For questions 4 through 6, they want you to use the distributive property. There is no way of solving them without having either the length of both sides or the total area.