Two unknown charges lie on the x axis separated by some distance. The force on one of these charges, say q1, is 34.4 Newtons directed in the negative x direction. If the amount of this charge is doubled and it changes sign (now -2 q1), but the location of both charges does not change, what is the electric force on q1 now in Newtons? Indicate the negative x direction by including a negative sign in the answer, but omit a sign for the positive x direction.