Final answer:
To translate 'less than x is equal to 13' into a mathematical equation, use x < 13.
Step-by-step explanation:
To translate the phrase 'less than x is equal to 13' into a mathematical equation, we can use the less than symbol (<) to represent 'less than' and the equal sign (=) to represent 'is equal to'. So the equation would be:
x < 13
This means that the value of x is less than 13. For example, x could be any number between 1 and 12.9999.