Ok to solve your problem let us first establish the formula:
x = represents the number
3x = three times that number
Proceed as 3x - 9 = 100
3x = 100 + 9
3x = 109
x = 109 / 3
x = 36 1/3
is the difference between thrice a number and 9 is 100
Reference: https://brainly.ph/question/423618
