Answer:
because they allow us to make direct comparisons
Step-by-step explanation:
Usually when you see f(x) or as yours is f(6) f with parenthesis is just a fancy way of saying y= so basically you plug six in for the x values of your question
The equation for a line is mx + b = y where m is the slope and b is the y intercept. To find the slope, we need to use the equation
.



Therefore, m is equal to -1. Normally, we would then have to plug in m and one of the points to find b. However, because the point (0,5) is the y-intercept (the y-intercept is the point on the line where x is equal to 0), we can skip this step and go straight to forming the final equation, which is
.