Answer:
c = 6 and d = 8, I suspect you know the answer and just need to know how
d is not 8
Step-by-step explanation:
Disclaimer the student needs to verify the solution for typos, algebra and calculations
9c + 2d = 54
с + 2d = 6 I would multiply this equation by -1, then add both equations
I picked -1 to get rid of 2d terms but an easier way would
have been to just subtract the bottom eq from the top eq
-с - 2d = -6
9c + 2d = 54
(-c + 9c) + (-2d + 2d) = -6 + 54 add the like terms
8c + 0 = 48
8c = 48
c = 6 as you said but now solve for d using
с + 2d = 6 c = 6 solve for d
6 + 2d = 6 subtract 6 from both sides
6 - 6 + 2d = 6 - 6
0 + 2d = 0
d = 0/2
d = 0 not 8
9c + 2d = 54
с + 2d = 6
-------------------- subtract
8c = 48
c = 6
