SOLUTION: Please help me solve this problem by the elimination method. I am having a lot of trouble understanding how to solve for y after I solve for x. And I have a problem solving for x

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Question 362918: Please help me solve this problem by the elimination method. I am having a lot of trouble understanding how to solve for y after I solve for x. And I have a problem solving for x when a fraction is involved as is in this problem.
0.3x - 0.2y=4
0.4x - 0.5y=-55/17
I understand that the first equation will be 0.3x = 4, and the second will be 0.4x=-55/17;
Don't know what to do after this. I do not get the elimination method.
Thank you.

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
1.0.3x+-+0.2y=4
2.0.4x+-+0.5y=-55%2F17
If you don't like fractions or decimals, get rid of them by multiplying.
Multiply both equations by 10 to get rid of decimals.
1.3x-2y=40
2.4x-5y=-550%2F17
Now multiply the second equation by 17 to get rid of the fraction.
2.68x-85y=-550
.
.
.
OK now you have 2 equations and you want to get rid of one variable.
1.3x-2y=40
2.68x-85y=-550
If you multiply the first equation by 85 and the second equation by (-2) and add them, you can eliminate y and solve for x.
85%283x-2y%29%2B%28-2%29%2868x-85y%29=85%2840%29%2B%28-2%29%28-550%29
255x-170y-136x%2B170y=3400%2B1100
119x=4500
highlight%28x=4500%2F119%29
Now that you have x, use either equation to solve for y.
Both equations will work.
1.3x-2y=40
3%284500%2F119%29-2y=4760%2F119
13500%2F119-2y=4760%2F119
-2y=%284760-13500%29%2F119
-2y=8740%2F119
highlight%28y=-4370%2F119%29