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.
The answer to the question they gave you is D
Answer:

Step-by-step explanation:
Given

Required
Find 

Express 32 as an exponent

By comparison:


So:

Option B. 12/ 125 is the answer.
Explanation
Total umber of sour ball candies = 50
Number of lemon candies = 12
Hence the probability to get a lemon candy is = 12/50
Number of cherry sour balls = 20
So, the probability to get a cherry sour ball = 20/50
So, to get the joint probability for a random selection to either get a lemon or cherry candy, we will multiply both the probabilities.

= 