If you know 4×5 =20 how can you use the commutative (order) property of multiplication to find 5*4

Cam bought some used books for $4.95. he paid $0.50 each for some books and $0.35 each for the others. he bought fewer than 8 books at each price. how many books did cam buy?

Angle mno is s rotated 180 degrees counterclockwise about the origin to form angle m’n’o’. which statement shows the measure of angle m’n’o’?

Which expression can be used to determine the slope of the line that passes through the points -6, three and one, -9