Refrigerator a costs $600 and $50 per year for the electricity to operate it. refrigerator b costs $1200 and $40 per year for the electricity to operate it. define the two variables. write a linear equation for the cost of owning refrigerator a and refrigerator b.

For a field trip to the zoo, 4 students rode in cars and the rest filled nine busess. how many students were in each bus if 472 students were on the trip

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.

Write the equations in logarithmic form 7^3=343