SOLUTION: Solve by substitution. X+3Y=15 2x-3y=3

Question 747338: Solve by substitution.
X+3Y=15
2x-3y=3
Found 2 solutions by lynnlo, timvanswearingen:
Answer by lynnlo(4176) (Show Source): You can put this solution on YOUR website!
x=-12,,,,,,,,,,y=9
Answer by timvanswearingen(106) (Show Source): You can put this solution on YOUR website!
To use substitution, you need to solve for one of the variables in terms of the other. I usually try to go for the easiest one, so I'm going to solve for x in the first equation.

Subtract 3y from both sides:

Now you have solved for x in terms of y.
Next, use the OTHER equation, not the one you used to solve for x.

Plug in 15-3y for x.

Distribute,

Combine like terms,

Subtract 30 from both sides,

Divide both sides by -9:

Now, plug in 3 for y into the equation where x is by itself.

Now you have x and y, so your answer is the ordered pair:

(6, 3)
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