Answer:
38 mpg
Step-by-step explanation:
Initial efficiency = 39 mpg
Initial speed = 40 mph
Final speed = 50 mph
The efficiency drop between 40 mph and 50 mph is given by:

The total efficiency drop from 40 to 50 mph is:

Therefore, the efficiency at 50 mph is:

If you graph out y = x^2 - 1, you'll see that it is a curved parabola. It is not a straight line. So visually this shows the equation is not linear. It's considered nonlinear.
Algebraically, the given equation does not fit the form y = mx+b which is slope intercept form. So this is more confirmation that we do not have a linear function.
Answer:
100°
Step-by-step explanation:
The sum of the angles in a triangle is 180°
180°-30°-50°=100°