Question

What is the solution of the system of equations c + 4d = 8 and c = 4d - 6

Answer 1

C+3D=8
C=8-3D
C=4d-6
8 -3d =4d-6
8+6=4d+3D
14=7d
D=2

Answer 2

Rewrite the second equation in same form as the first So we have

c + 4d = 8

c - 4d = -6     Now add:-

2c + 0 = 2
2c = 2

c = 1  

Now substitute c = 1 in the first equation:-

1 + 4d = 8
4d = 7

d =  7/4  = 1 3/4

Answer c = 1 and d = 1 3/4  Answer