Question

solve by elimination pleasee

a+b+c=-3
3b-c=4
2a-b-2c=0

how do you work it out

Answer 1

will take a min

Answer 2

OK so first we will name the equations to make things simple
1. a + b + c = -3
2. 3b - c = 4
3. 2a-b-2c = 0

First solve for c in equation 2,
c = 3b-4

Then plug c into equation 1,
a + b +3b - 4 = -3 and solve for a,
a = 4b =1
a = 1 - 4b

Then plug a and c into equation 3,
2(1-4b) - b -2(3b-4) = 0, solve for b,
2-8b-b-6b+8 = 0
10 - 15b = 0
b = 10/15

Answer 3

then plug b into the c and a equations,
c = 3(10/15) - 4 = 2 -4 = -2
a = 1 -4(10/15) = -25/15

Answer 4

SO you have a = -25/15, b = 10/15, and c = -2