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Question 231267: If i was given this problem to solve algebraically --> 8x + 5y = 6
-3x - 9y = -45.....and to apply the elimination method, it was rewritten as 24x + 15y = 18
-24x - 9y = -45.....what mistake was made?????
Answer by unlockmath(1688)   (Show Source):
You can put this solution on YOUR website! Hello,
Let's take a look at this. I take it you were given 2 equations.
8x + 5y = 6 and -3x - 9y = -45
What happened was the first equation was multiplied by 3. (Note, you need to multiply all the terms in the equation. Then the equation looks like this:
24x + 15y = 18 Now let's multiply the second equation by 8 which will be:
-24x - 72y = -360 Let's add these equations together, which gives us:
-57y = -342 Now solve for y by dividing each side by -57.
y = 6
Now we can plug 6 into y in the original equation:
-3x - 9(6) = -45 Solve
-3x - 54 = -45 Add 54 to both sides.
-3x = 9 Divide by -3
x = -3
So the answer is x = -3 and y = 6
Plug these into the original equation and it should be correct.
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