Solve the system. -a+4b+2c=-8 3a+b-4c=9 b=-1 a.(0,11) ,-1,2) c.(1,1,-2) d.(2,-1,-1)

D.(2,-1,-1)

Step-by-step explanation:

-a+4b+2c=-8

3a+b-4c=9

b = -1

Substitute b=-1 into the other equations

-a -4 +2c = -8

3a -1 -4c =9

Multiply the first equation by 2 so we can eliminate c

-2a -8 +4c = -16

Add this to the second equation

-2a -8 +4c = -16

3a -1 -4c =9

a -9 = -7

Add 9 to each side

a-9+9 = -7+9

a =2

b=-1

Now we need to find c

-a +4b +2c = -8

-2 -4 +2c = -8

-6+2c = -8

Add 6 to each side

-6+6 +2c = -8+6

2c = -2

Divide by 2

2c/2 = -2/2

c=-1

(2,-1,-1)

a

step-by-step explanation: