Question

C+d=6
c-d=0
solving systems by substituting

Answer 1

c = 3 , d = 3

Explanation:

c + d = 6 ( subtract c from both sides )

d = 6 - c → (1)

c - d = 0 → (2)

substitute d = 6 - c into (2)

c - (6 - c) = 0

c - 6 + c = 0

2c - 6 = 0 ( add 6 to both sides )

2c = 6 ( divide both sides by 2 )

c = 3

substitute c = 3 into (1)

d = 6 - 3 = 3

solution is c = 3 , d = 3