This is not a Linear equation. I can tell from the graph because it’s not a straight line, but actually, it’s a circle, and I can tell from the equation because it has exponents.

y=1/2 x3

This is not a Linear equation. I can tell from the graph because it’s not a straight line and will never be because it has curves. I can tell from the equation because it has exponents.

x=4

This is a linear equation. I can tell from the graph because it’s a straight line. I can tell from the equation because it has the exponent of one.

2x-3y=12

This is a Linear equation. I can tell from the graph because it’s a straight line. I can tell from the equation because it only has the exponent of one.