Question

Solve the system.

Answer 1

Answer:

Option D is right,.

Step-by-step explanation:

-a+4b+2c=-8   ... i

3a+b-4c=9      ... ii

b=-1                 ... iii

Substitute the value of b, in i and ii

-a-4+2c =-8 or -a+2c = -4

and 3a-1-4c = 9 or 3a -4c =8

Now we have two equations in two variables

-a+2c =-4 and 3a-4c =8

a = 2c+4:  substitute this in the other equatin.

3(2c+4)-4c =8 Or 2c +12 =8

2c =-4 or c = -2

Substitute in -a+2c =12

-a-2 = -4

a = -2+4 =2

a=2, b=-1 and c =-1 is the solution.