Is the expression (3x) · x + 4 linear?

no

Step-by-step explanation:

the (3x)(x) will simplify to 3x^2, and when the leading coefficient (the coefficient with the largest exponent) has an exponent of 2 or greater, then it is not linear, as a linear expression must have a leading coefficient with an exponent of 1.

We need the scenario.

Step-by-step explanation:

Generally the independent variable is the thing you are changing and the dependent variable is being changed based on the independent variable.

Ex:

y= x+1

x is the independent variable because you can put in whatever value you want in and y is the dependent variable because its value depends on what you choose for x if that makes sense. I would need you scenario to be able to tell you exactly what it is.