Question 243719: Solve using the substitution method.
y = 2x - 5
3x + y = 15
Answer by unlockmath(1688)   (Show Source):
You can put this solution on YOUR website! Hello,
Let's first set both equations up so they have the variables on one side.
In the first equation subtract 2x from both sides so it will look like:
-2x + y = - 5
3x + y = 15
OK, Now let's multiply the first equation by -1 to give us:
+2x - y = + 5
3x + y = 15
With this we can add both equations to be:
5x=20 Divide both sides by 5:
x=4
Now in the original equation replace x with 4:
y = 2(4) - 5 Do the calculation gives us:
y=3
We now have x=4 and y=3. Plug these into both equations to see if they work.
RJ Toftness
www.math-unlock.com
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