Hi, here is a homework problem which i'm absolutely stuck on. A charge of -3.2 × 10-9 C is at the origin and a charge of 7.3 × 10-9 C is on the x-axis at x = 3 m. At what location on the x-axis is the electric field zero? I've asked my professor for help on this, and his explanation wasn't very good. What I got out of it was the following. The location will exist somewhere to the left of the origin. Also, this may be wrong, but am I supposed to solve for r in the following equation: kQ1\r^2 = kQ2 \ (r^2 +3)? I've tried that, but a bunch of the answers I come up w/ seem not to be right. Any help would be greatly appreciated. Thanks in advance.