Final answer:
The algebraic expression for 5 groups of x is written as 5x, where x is the variable representing the number of items in each group.
Step-by-step explanation:
The algebraic expression for 5 groups of x is written as 5x. This expression indicates that x is being multiplied by 5, which is equivalent to saying that we have five groups consisting of x items each. The use of x is arbitrary, and it simply serves as a placeholder or label in an equation that can be substituted with any other variable, if done consistently.