The first step is to isolate the #n# term by subtracting #color(red)(7.9)# from each side of the equation which will also keep the equation balanced:
#-n/1.6 + 7.9 - color(red)(7.9) = 8.4 - color(red)(7.9)#
#-n/1.6 + 0 = 0.5#
#-n/1.6 = 0.5#
Next, we will multiply each side of the equation by #color(red)(-1.6)# to solve for #n# while keeping the equation balanced:
#n/(-1.6) xx color(red)(-1.6) = 0.5 xx color(red)(-1.6)#
#n/(color(red)(cancel(color(black)(-1.6)))) xx cancel(color(red)(-1.6)) = 0.5 xx color(red)(-1.6)#
#n = -0.8#
