Use the intercept method to graph the equation y=-3

What if I write the equation like this:

y = zero x - 3.

Now you know that the slope of the line is zero and its y-intercept is - 3.

That's a horizontal line that crosses the y-axis at - 3. And just like the equation says, the value of 'y' doesn't depend on 'x'. It's - 3 everywhere.