9514 1404 393
Answer:
B) -3
Step-by-step explanation:
There are methods for finding only c. Cramer's rule is one of them. It involves finding two determinants and taking their ratio. Here, we choose a more ad hoc approach. It appears that the value of b can be found by combining the last two equations.
(1/2)(2a +4b -2c) -(a -3b -c) = (1/2)(12) -(-4)
5b = 10
b = 2
Now, we can substitute this value into the first two equations. This gives ...
5a +c = -8
a - c = 2
Subtracting 5 times the second from the first gives ...
(5a +c) -5(a -c) = (-8) -5(2)
6c = -18 . . . . simplify
c = -3 . . . . . . divide by 6
The value of c is -3.
