# Calculating Electric Field (what am i doing wrong?)

I believe this may be a problem with the website where I do my homework. Please check my solution and see if there is a mistake or if I am missing something. The following is the arrangement of point charges in the problem:

8.26 micro C ---2.93 cm---> P1 ---1.59 cm ---> 4.94 micro C ---2.73 cm--->-1.23 micro C

What is the electric field at point P1? Coulomb's constant is 8.98755 Nm^2/C^2.

I convert all distances to meters which gives:
r1 = 2.93 cm = .0293 m
r2 = 1.59 cm = .0159 m
r3 = 1.59 cm + 2.73 cm = 4.32 cm = .0432 m

Since all points are on the X-axis only, I do not have to worry about any Y-axis components. I perform the following steps:

E1 = (8.98755e+9 Nm^2/C^2)(8.26e-6 C)/.0293 m^2 = +86474115.0159 N/C
E2 = (8.98755e+9 Nm^2/C^2)(4.94e-6 C)/.0159 m^2 = -175620018.987 N/C
E3 = (8.98755e+9 Nm^2/C^2)(1.23e-6 C)/.0432m^2 = +5923507.4267 N/C

E1-E2+E3 = -83222396.5444 N/C

My homework website says the answer is wrong. We do not need to worry a obout significant figures in the answer. What errors can you see, or what am I missing.