Which of the following describes a linear function?

it is a straight line that passes through the origin.
its y-values and x-values increase at a nonconstant rate.
it is a straight line in one portion and a curve in another portion.
its y-values increase at a nonconstant rate as its x-value increases.

It is a straight line that passes through the origin

step-by-step explanation:

step 1: solve one of the equations for one of the variables. let's solve the first equation for y:

step 2: substitute that equation into the other equation, and solve for x.

step 3: substitute x = 4 x = 4 x=4 into one of the original equations, and solve for y.