Learn how to evaluate a function using an expression

The video tutorial explains how to solve a more complex mathematical problem involving expressions. The instructor guides through evaluating an expression by substituting a variable, emphasizing the use of parentheses and the distributive property. The process is similar to simpler problems but requires careful application of mathematical rules to reach the final result.

How does the complexity of this problem differ from the previous one mentioned?

What does the teacher mean by using parentheses in the expression?