First, subtract #color(red)(4.7)# from each side of the inequality to isolate the #x# term while keeping the inequality balanced:

#-color(red)(4.7) + 4.7 - 2.1x > -color(red)(4.7) - 7.9#

#0 - 2.1x > -12.6#

#-2.1x > -12.6#

Now, divide each side of the inequality by #color(blue)(-2.1)# to solve for #x# while keeping the inequality balanced. However, because we are multiplying or dividing and inequality by a negative number we must reverse the inequality operator:

#(-2.1x)/color(blue)(-2.1) color(red)(<) (-12.6)/color(blue)(-2.1)#

#(color(blue)(cancel(color(black)(-2.1)))x)/cancel(color(blue)(-2.1)) color(red)(<) 6#

#x color(red)(<) 6#

The graphs for this is:

graph{x < 6 [-10, 10, -5, 5]}