SOLUTION: How do I find the system of equations 3y+2z=12 and y-z=9?

Question 175700: How do I find the system of equations 3y+2z=12 and y-z=9?
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!

Start with the given system of equations:

Multiply the both sides of the second equation by 2.

Distribute and multiply.

So we have the new system of equations:

Now add the equations together. You can do this by simply adding the two left sides and the two right sides separately like this:

Group like terms.

Combine like terms. Notice how the z terms cancel out.

Simplify.

Divide both sides by to isolate .

Reduce.

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Now go back to the first equation.

Plug in .

Multiply.

Subtract from both sides.

Combine like terms on the right side.

Divide both sides by to isolate .

Reduce.

So our answer is and .

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