Answer:
The equation 2 has a graph which is a straight line.
Explanation:
Why?
We can know which of the given equations has a graph which is a straight line just checking the exponents of the variables.
We must remember that every variable that has an exponent equal or higher than 2 (quadratic) will not have a straight line as a graphic.
So, checking the exponents from the given equations, we have:
Hence, we can see that the only equation that has a linear term (straight line graph), is the second equation.