SOLUTION: I am having trouble solving this equation using the elimination method. 6a + 2b = -4 -6a + b = 7 Thanks for your help.

Algebra ->  Expressions-with-variables -> SOLUTION: I am having trouble solving this equation using the elimination method. 6a + 2b = -4 -6a + b = 7 Thanks for your help.      Log On


   

Question 679897: I am having trouble solving this equation using the elimination method.
6a + 2b = -4
-6a + b = 7
Thanks for your help.
Found 2 solutions by Alan3354, ReadingBoosters:
Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
6a + 2b = -4
-6a + b = 7
-------------- Add

Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
Add them, notice that the first equation has 6a and the second has -6a; the a variable will cancel.
6a + -6a + 2b + b = -4 + 7
3b = 3
b = 1
...
Multiplty the second equation by -2
-2(-6a+b=7) to get (12a + -2b = -14
Then add to the first equation
6a + 12a + 2b + -2b = -4 + -14
18a = -18
a = -1
...
Check
6(-1) + 2(1) = -6 + 2 = -4
-6(-1) + 1 = 6 + 1 = 7
CORRECT!
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