You can put this solution on YOUR website! Hi! The equation of a line is y = mx + b where m is the slope and b is the y intercept. We know the slope is -2 and the y-intercept is the y value of the point on the line such that x = 0. Since the line passes through (0, 4) the y-intercept is 4. So, the equation is y = -2x + 4.