12.50+0.40e=14.75+0.25e
-12.50 -12.50 Subtract 12.50 to elimanate on the right side to isolate e
0.40e=2.25+0.25e left from subtracting 12/50
-0.25 -0.25e subtract 0.25e to put e on one side.
0.15e=2.25 left from subtracting 0.25 e
0.15e/0.15=2.25/0.15 divide to isolate e and to get you're answer
e=15
Hope it helps!
