First thing's first, we can determine the gradient, m, simply by looking at the points. The gradient is determined by how much the value of y increments (or decrements) for each increase of 1 on the x axis.
Every time x increases by 1, y decreases by 4, meaning our gradient is -4.
We are also able to determine our constant, c, by seeing where our line will cross the y axis. In this case, there is a point dead-on the y axis at (0, -2), meaning our constant is -2.
With this information, we can put together the linear equation, y = -4x -2.
