4d + 7e = 68
-4d – 6e = -72
We would eliminate d by adding both equations. We have
4d + - 4d + 7e + - 6e = 68 + - 72
4d - 4d + 7e - 6e = 68 - 72
e = - 4
Substituting e = -4 into 4d + 7e = 68, we have
4 * - 4 + 7e = 68
- 16 + 7e = 68
7e = 68 + 16
7e = 84
e = 84/7
e = 12
Thus,
d = - 4, e = 12
