Three x is five less than twice x

[math_celebrity]

Twice x means we multiply x by 2:
2x

five less than twice x
2x - 5

Three x
3x

The word is means equal to. Set 2x - 5 equal to 3x for our algebraic expression:
2x - 5 = 3x

If the problem asks you to solve for x, subtract 2x from each side
x = -5