Answer: 0
Step-by-step explanation: In order to identify the y-intercept of this equation, we want to get this equation into slope-intercept form which is more commonly known as y = mx + b form.
The problem is our equation doesn't match up quite so well with the formula y = mx + b. Our slope or m which is represented by the coefficient of the x term is clearly +4 but what is our y-intercept or b?
Well y = 4x can be thought of as y = 4x + 0 so you can see that our b or y-intercept equals 0.
