(d) \( y=x-18 \)

Let's take a joyful ride through the world of equations! This linear function, \( y = x - 18 \), is like a fun roller coaster, with a slope of 1, meaning for every step you take to the right on the x-axis, you also go up one notch on the y-axis. And whoo, it's down 18 notches! Its y-intercept is at (0, -18), where the ride starts. Graphing this line will give you a straight dash through the Cartesian plane; you can even visualize it connecting points like a tightrope walker balancing above the grid! In real-world applications, you might encounter such linear equations in budgeting or project planning. If you think about it, \( x \) could represent your income while \( y \) is your savings after setting aside a flat rate of $18 for essentials every month. So if you earn $100 in a month, after allocating for those essentials, you’ll have $82 left! This equation can help you quickly assess how changes in income impact your savings. So go ahead, crunch those numbers and watch your savings climb!