Please help me on this thanks, I got the right answer but I still don’t understand

His present age is 13 years.
The words problem can be solved as follows:
let
his present age = x
Therefore,
3(x + 5) = 54
Hence,
3(x + 5) = 54
3x + 15 = 54
subtract 15 from both sides
3x + 15 - 15 = 54 - 15
3x = 39
divide both sides by 3
3x / 3 = 39 / 3
x = 13
learn more on words problem here: https://brainly.com/question/11551965
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