The difference between three and seven times a number

Question

Write an expression that matches this phrase

Answer 1

3 - 7x

or

7x-3

"difference" usually means the positive difference or absolute value of the difference: |7x-3| = |3-7x|

subtract one from the other, then change the sign to positive, if you get a negative difference, so that the difference is always positive.

|7x-3| = 7x-3 if x>3/7 but = -(7x-3)=3-7x if x<3/7

|3-7x| = 3-7x if x<3/7 but = -(3-7x)=7x-3 if x>3/7