Urgent!!!!! Please help!!!!!!! 10 point question!!!!!

When solving systems of equations, how do you determine what method to use?

This is an Algebra 1 question.

That really depends on the type of equations, for example:

(1)
x + 2y = 5
3x + 7y = 12

Here is easier to find x from first equation, and plug it into the 2nd equation.

x + 2y = 5 ===> x = 5 - 2y ........ plug into 2nd

3(5 - 2y) + 7y = 12
15 - 6y + 7y = 12
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(2)
32x + 6y = 122
4x + 3y = 103

Here is easier to divide first equation with 2, and than subtract the equations.

16x + 3y = 61
4x + 3y = 103
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16x - 4x + 3y - 3y = 61 - 103 .........3y cancels

12x = - 42
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Both of the methods should give the same results.