4.Find the solution mentally. a. 3 x -4 = a
b. b x (-3) = -12
c. -12 x c = 12
d. d x 24 = -12

3*-4=-12
4*-3=-12
-12*-1=12

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.