Question 114656: This is a problem that I need to solve by system of elimination and then check the answer. The problem is:
{3a+2b=2}
{a+6b+18}
How do I solve this, and check the problem. Please help.
Thank You
Answer by jgr45(31)   (Show Source):
You can put this solution on YOUR website! First of all, I'm assuming you meant a+6b=18 for the second equation. Personally, I would subtract 6b from both sides from the second equation and then use substitution, but elimination works just as well, of course. Either method will give you the same answer.
First, multiply the second equation by -3. To do this, you must multiply each term by -3. The first equation will remain unchanged:
3a + 2b = 2
-3a - 18b = -54
Now combine (the a's will cancel out):
-16b = -52
Divide by -16:
b =  , or 3 or 3 , or 3.25.
Now, sub 3.25 for b in either equation to find a. I'll choose the first:
3a + 2(3.25) = 2
3a + 6.5 = 2
3a = -4.5
a = -1.5
So the point of intersection of those two lines is (-1.5, 3.25).
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