Functions 6 and 7 are linear, 8 is not. This means 6 and 7 have a degree of 1. Since 8 is a quadratic, it has a degree of 2.
The slope is 1 for function 6 and 5 for function 7. Remember, in slope-intercept format, linear equations are written as y=mx+b. X and Y stand for coordinates you can plug in, m represents the slope of the line, and b represents the y-coordinate of the function’s y-intercept. I assume you are familiar with these terms so I won’t explain them.
Number 9 is linear, and you can tell because f(x), which is the output, increases with a constant difference as x increases by 1. In other words, the delta y and delta x is the same between all points.
Number 10 is clearly not linear, because two different x values have the same y value. This is a parabola.
I recommend you graph some of these functions for practice, so you can visualize it better. Imagine the functions as machines. You input a number (x) and you get a number out (y).
For example, in the function f(x)=3x+5, I can input any x, let’s take x as 6, and when I plug it in, I’ll get an output, f(x). 3(6)+5=18+5=23. So my f(x)=23 when x is 6.
