Question 747338: Solve by substitution.
X+3Y=15
2x-3y=3
Found 3 solutions by lynnlo, timvanswearingen, ikleyn:
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)
Answer by ikleyn(53066)  (Show Source):
You can put this solution on YOUR website! .
Solve by substitution.
X+3Y=15
2x-3y=3
~~~~~~~~~~~~~~~~~~~~~~~~
You have two equations
x + 3y = 15, (1)
2x - 3y = 3. (2)
They want you solve it by the substitution method.
For it, from equation (1) express x = 15 - 3y and substirute it into equation (2), replacing x there
2*(15-3y) - 3y = 3.
Simplify it and find 'y'
30 - 6y - 3y = 3,
30 - 3 = 6y + 3y,
27 = 9y
y = 27/9 = 3.
Now x = 15 - 3y = 15 - 3*3 = 15*9 = 6.
ANSWER. x = 6, y = 9.
You may substitute these values into original equation
to make sure that this answer is correct.
Solved.
The answer in the post by @lynnlo is incorrect, so please ingnore it.
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