Question

Use the elimination method to solve the system of equations.
a+6b= -1
a +2b = -5

Answer 1

subtract one equation from the other.

Since there is already the same amount of a's in both equations, this term should drop out and you should be able to solve for b

Answer 2

8b = -6/8

Answer 3

Try again

Answer 4

a + 6b = -1
- (a + 2b = -5)
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Answer 5

8b=-6

Answer 6

you are subtracting. The negative sign needs to be distributed to each term

Answer 7

4b=4

Answer 8

correct, so what is b?

Answer 9

1

Answer 10

Correct, so now that we know b, we plug that in to one of the equations to solve for a, it doesn't matter which one. I usually choose the easiest of the 2

Answer 11

I must note that if 2 equations don't have the same amount of either unknowns, you are allowed to multiply an equation by a scalar to fix this problem.

Ex)
2a + 6b = -1
(a + 2b = -5)*2

2a + 6b = -1
2a + 4b = -10

Now you could eliminate. If you wanted to could have multiplied by a -2 so that the equations looked like...

2a + 6b = -1
-2a + -4b = 10

Now you can add the equations instead of subtract. This is what I try to do. I don't like subtraction that much

Answer 12

a+6(1) = -1
a+6= -1, a =-1 +(-6)
a=-7

Answer 13

correct. good job

Answer 14

Thanks