1. The problem statement, all variables and given/known data 2. Relevant equations E = -dV/dx ? 3. The attempt at a solution not really sure how to do this problem. I think I understand E field is negative of slope of V/x, but i'm getting it wrong. just looking at it, I see V=-2 at x=7.5. so the E field to right of x= 5 is y2-y1/x2-x1= 2/2.5 = 0.8. to the left of it I guess it's -0.8 (V/m). I tried both answer but its wrong.