\( 5 b - 6 a \)

The expression \( 5b - 6a \) showcases a powerful aspect of algebra: linear combinations! Here, two variables, \( a \) and \( b \), are combined in such a way that each term is scaled by a coefficient (5 for \( b \) and -6 for \( a \)). This is fundamental in equations and systems of equations, where you often need to find values for the variables that satisfy specific conditions. In real-world scenarios, such expressions are ubiquitous! For example, if you were designing a budget for a project, \( a \) could represent the number of hours worked by one team member, while \( b \) could reflect hours from another. Then, \( 5b - 6a \) might help you analyze cost vs. time trade-offs, making it easier to visualize how changes in one variable impact overall efficiency.