It’s a linear because the line is straight and linear, when you take of the ar, it’s line. Nonlinear means not a line. The line would not be straight and the line will a curve. Like noodles. Noodles aren’t straight, but when you make it straight it’s a linear.
The answer would probably be 18 degrees below normal because the absolute values of the rest are 8 not 18 which is the absolute value of 18 degrees below normal.
