Find the slope by comparing the values within one column. If you subtract 1 from -3, you'll get the value of 4. You then notice that each time, the value increases by 4. Since the y= column is increasing by one, the value therefore remains constant because 4 divided by 1 is always 4.
Now, to find the coefficient, just look at where the y value is 0. Whatever number x is when the value is 0, that will be your coefficient because it is the y-intercept (the initial starting value); in this case -3