When 20 is subtracted from 3 times a certain number, the result is 43

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A certain number means an arbitrary variable, let's call it x
x

3 times x
3x

20 is subtracted from 3 time x
3x - 20

The result is means equal to, so we set 3x - 20 equal to 43 for our algebraic expression
3x - 20 = 43

If you need to solve this, use our equation calculator:
x = 21