5x+6y=5
10x+12y=10
Solve by the elimination method?
2009-02-14 4:06 pm
回答 (5)
2009-02-14 4:14 pm
✔ 最佳答案
5x+6y=5 --------(1)10x+12y=10 ----(2)
You can eliminate either x or y. Let us eliminate x.
Multiply equation (1) by -10 and equation (2) by 5
-50x-60y = -50
50x+60y = 50
Add:
0x =0
This shows the system is inconsistent and there is no unique solution.
2009-02-14 4:28 pm
no. substitution. 10x+12y=10 becomes 12y=10x-10. divide by 12 on both sides...so it's y=5/6x-5/6. now plug that into 5x+6y=5.
so its 5x+6(5/6x-5/6)=5
5x+30/6x-30/6=5
5x+5x-5=5
10x-5=5
10x=10
x=1
plug x into 10x+12y=10
10(1)+12y=10
10+12y=10
12y=0
y=0
so: x=1 and y =0
so its 5x+6(5/6x-5/6)=5
5x+30/6x-30/6=5
5x+5x-5=5
10x-5=5
10x=10
x=1
plug x into 10x+12y=10
10(1)+12y=10
10+12y=10
12y=0
y=0
so: x=1 and y =0
2009-02-14 4:19 pm
multiply 5x+6y=5 by -2 to get -10x-6y=-10 then add to 10x+12y=10, and you get 0=0, no solution, cuz you want to eliminate either the x or y term so that you can solve for the other and you cannot because both terms are eliminated
2009-02-14 4:17 pm
5x + 6y = 5
10x + 12y = 10
5x + 6y = 5
2(5x + 6y) = 2(5)
10x + 12y = 10
...10x + 12y = 10
–) 10x + 12y = 10 (subtraction)
--------------------------------
0
(infinite solutions)
10x + 12y = 10
5x + 6y = 5
2(5x + 6y) = 2(5)
10x + 12y = 10
...10x + 12y = 10
–) 10x + 12y = 10 (subtraction)
--------------------------------
0
(infinite solutions)
2009-02-14 4:10 pm
You could use Cramer's law, or you could use substitution.
This is basically finding the intersection between the two lines.
However, these two lines are parallel and therefore have no solution because they have no intersection.
The slope of line 1 is -5/6 and the slope of line 2 is also -5/6.
This is basically finding the intersection between the two lines.
However, these two lines are parallel and therefore have no solution because they have no intersection.
The slope of line 1 is -5/6 and the slope of line 2 is also -5/6.
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