A window cleaner has enough supplies to clean 21 windows per office building on a certain number of buildings. They can also clean the windows of a school with 42 windows. Altogether, there are enough supplies to clean 126 windows. How many office buildings can be washed? Identify the equation that would be used to solve this problem algebraically.(1 point)

Responses

42x+21=126
42 x plus 21 equals 126

21x+42=126
21 x plus 42 equals 126

42x−21=126
42 x minus 21 equals 126

21x−42=126