SOLUTION: Solve the system by substitution. x+y=12 y=2x

Question 102597: Solve the system by substitution.
x+y=12
y=2x
Answer by mjgulinello(10) (Show Source): You can put this solution on YOUR website!
Substitution means plugging one equation into the other.
So if we plug y = 2x into the first equation we get

Combine like terms

Divide both sides by 3

Then we can plug in that result to the second equation.

We can check this by plugging it back into the first equation.

12=12
Checks out.
That's it for this problem.
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