Question

15 less than 4 times a number is 9 find the number

Answer 1

Translating it into math figures:
4*?-15=9
lets say the question mark is x:
4*x-15=9
4x-15=9
adding 15 from both sides:
4x=24
now divide both sides by 4:
x=6
just to make sure it's correct, put it in the original equation
4*6-15=9
24-15=9
:)

Answer 2

4x - 15 = 9
4x = 9 + 15
4x = 24
x = 24/4
x = 6

hope this helps you