Final answer:
The phrase 'x decreased by 8' simply means that 8 is subtracted from the variable x, represented mathematically as x - 8.
Step-by-step explanation:
The expression 'x decreased by 8' in words means that the number represented by x is to be reduced by 8. In a mathematical form, this is written as x - 8.
This expression is used in various mathematical contexts, such as solving equations, understanding functions, or applying mathematical operations in word problems.