Two particles having charges of 0.580 nC and 20.9 nC are separated by a distance of 1.10 m .

Question

Where would the net electric field be zero if one of the charges were negative?
Enter your answer as a distance from the charge initially equal 0.580 nC .

keq1/r^2 = keq2/(1.1-r)^2 (the ke's cancel out)
-.580 x 10^-9/r^2 = 20.9 x 10^-9/(1.1+r)^2
(20.9 x 10^-9)r^2 = (-.580 x 10^-9)(1.1+r)^2
(-36.034)r^2 = (r+1.1)^2
-7.003r = 1.1
r = .157
I added that to the 1.1 to get the total distance of 1.257 m, but that answer is wrong. Could someone please help me figure out what I'm doing wrong?