Let's analyze the functions in the image to determine whether they are linear or nonlinear:

1. $y = 3 - x^3$:

   • This function contains the term $x^3$, which is a cubic term. Any polynomial with a degree higher than 1 is considered nonlinear.
   • Answer: Nonlinear.

2. $y = 15$:

   • This is a constant function. A constant function is actually a special case of a linear function because it can be written as $y = 0x + 15$, which fits the form of a linear equation $y = mx + b$.
   • Answer: Linear.

3. $y = 11 + 5x$:

   • This function is in the form $y = mx + b$, which is a linear equation with a slope $m = 5$ and a y-intercept $b = 11$.
   • Answer: Linear.

Summary of answers:

• $y = 3 - x^3$ → Nonlinear
• $y = 15$ → Linear
• $y = 11 + 5x$ → Linear

Would you like more details on why each function is classified this way, or do you have any other questions?

Here are 5 related questions for further exploration:

1. What makes a function linear versus nonlinear in general?
2. Can a nonlinear function become linear under specific conditions?
3. How do we graph linear and nonlinear functions, and what are the differences?
4. Are all constant functions linear, and why?
5. How does the slope in a linear function affect its graph?

Tip: A linear function will always have the highest power of $x$ as 1 (or be a constant), while nonlinear functions have powers greater than 1 or other operations like square roots or exponentials.