24-8x=12y 1+5/9y=7/18x It's solve for elimination that make it harder
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The first equation can be simplified by dividing through by 4:

-6-2x=3y. The second equation can be simplified by multiplying through by 18:

18+10y=7x. It makes sense to have the variables on the left and the constant on the right:

2x+3y=6, 7x-10y=18. (One version of the equation has -24 and the other has 24, so we’ll start by assuming 24.)

Now to eliminate a variable. Multiply the first equation by 10 and the second by 3:

20x+30y=60, 

21x-30y=54.

Add the equations together: 41x=114, x=114/41. If we replace 24 with -24, then constant 60 becomes -60 and 41x=-6, x=-6/41. We have two possible values for x so we get two values for y:

3y=6-2x=6-228/41=18/41 or 6+12/41=258/41. So y=6/41 or 86/41.

If the question has -24 as the constant in the first equation then the solution is x=-6/41, y=86/41; if the constant is 24 then the solution is x=114/41, y=6/41.

Both answers look ugly, so perhaps there is another mistake in the question? Please check your pluses and minuses. For example, -24 and -(7/18)x would be solved as x=6, y=-6.

 

by Top Rated User (614k points)

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