Because since 17 can only be multiplied by it's self and one that's what the box is showing
His mistake was adding 12+2 when he was supposed to subtract.
Let's say that the unknown value here is c. Although we are given two points on the line, it is only necessary to use one as there is only one unknown value, so let's say we choose the point (6, -12) and substitute this into the equation:
-12 = 1(6) - c
-12 - 6 = -c
-18 = -c
c = 18
Thus the equation for the line is y = 1x - 18
Part A: it is linear because it is not curving and it consists of straight lines.
Part B: in side A it is increasing because it has a positive slope. In side b it is constant because the slope is 0 since it is straight. Finally, side C is decreasing because the slope is negative.
Part C: during side A the ant is crawling out of the hole in 2 seconds. After that, the ant stops for 2 more seconds as shown in side B. Then, he crawls back into the hole as shown by the decrease in distance due to the slope.
Hope this helps!!!