Find 3 by 7+(-6by11)+(-by 21)+5 by 20

If each bricks costs and he can only buy one brick how much will it cost him to get the material to put around the outside of his garden?

Felix wrote several equations and determined that only one of the equations has no solution. which of these equations has no solution?

What is the difference between –12 and –5? what is the distance between –12 and –7 on a number line? units