How old am I if 600 reduced by 3 times my age is 542?

Let's suppose your age is x.

The equation can be written as: 600 - 3x = 542.
Subtracting 542 from both sides of the equation: 600 - 542 - 3x = 0.
Simplifying: 58 - 3x = 0.
Adding 3x to both sides: 58 - 3x + 3x = 0 + 3x.
Simplifying: 58 = 3x.
Dividing both sides by 3: (58/3) = (3x/3).
Simplifying: 19.33 = x.
Rounding to the nearest whole number, your age is 19.