A rate is a special ratio in which the two terms are in different units. For example, if a 12-ounce can of corn costs 69¢, the rate is 69¢ for 12 ounces. ... 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.
You subtract X from four then you get your answer next to multiply your answer by two resulting in an answer….. the answer is the expression I wrote above.