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Solve the system using elimination5x+4y=123x-3y=18

User Fawzib
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1 Answer

21 votes
21 votes

Solve the following system of equations by elimination:

5x+4y=12

3x-3y=18​

We'll take advantage of the y's having opposite signs and select it for elimination:

Multiply the first equation by 3 and the second by 4:

3*(5x+4y)=3*12

15x+12y=36

Now for the second:

4*(3x-3y)=4*18​

12x-12y=72

Adding the two new equations:

15x+12y+12x-12y=36+72

Simplifying:

27x=108

Solving:

x=108/27=4

x=4

Now to find the value of y, we can use any of the equations:

5x+4y=12

Substitute x=4

5*4+4y=12

20+4y=12

4y=12-20=-8

Solving:

y=-8/4=-2

y=-2

Solution: x=4, y=-2

User Augusto
by
2.7k points
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