224k views
3 votes
In the system -12c+3d=6 and -3c+6d=-9, which expression could you use for substitution?. A. d=-1/2c-3/2. B.c=-2d+3. C.c=1/4d-1/2. D. d=4c-2

User TechFree
by
6.4k points

1 Answer

1 vote
The system:
- 12 c + 3 d = 6
- 3 c + 6 d = - 9
----------------------
The 1st equation:
- 12 c = - 3 d + 6 / * ( - 1) ( multiple both sides by -1 )
12 c = 3 d - 6 / : 12 ( divide both sides by 12 )
c = d / 4 - 1/2
Answer:
C ) c = 1/4 d - 1/2
User ShPavel
by
7.5k points