Answer:
2nd Option
3rd Option
Step-by-step explanation:
Linear equations are equations with a variable degree of 1.
Choice 1 is a function and a linear equation
Choice 4 is a linear equation but <em>not </em>a function
Quadratic equations are equations with variable degree of 2
(So choice 2 isn't a linear equation)
Cubic equations are equations with variable degree of 3
(So choice 3 isn't a linear equation)
