Question

When solving systems of equations by elimination do you solve for x or y first???

Answer 1

It really does not matter...
It depends on the given equation
if the coefficients of one variable are same in both then we try to eliminate it by adding/subtracting the two equations (depending on the signs of that variable in both the equations.
If both the variables have different coefficients in the two equations, then we try to equalise the coefficients for one of them....

I'll give a few examples.....

Answer 2

2x + 3y = 7 -------- (1)
2x - 7y = -11 -------- (2)

Here x has 2 as coefficients in both the equations, so we can subtract (2) from (1) and x will be eliminated

If we have
3x + 3y = 7 -------- (1)
2x - 3y = -11 -------- (2)

Here y has coefficient +3 in (1) and -3 in (2), so if we add (1) and (2) then y will be eliminated

Answer 3

Thank you so much. Have a nice day!

Answer 4

If we have
2x + 3y = 7 -------- (1)
5x - 5y = -11 -------- (2)

Here we have two choices
i) make coefficients of x same
ii) make coefficients of y same

If we make coefficients of x same, we do as follows:
we multiply (1) by 5 to get 10x + 15y = 35 ------(3)
we multiply (2) by -2 to get -10x + 10y = 22 ------(4)
Now we add (3) and (4) and x is eliminated

If we make coefficients of y same, we do as follows:
we multiply (1) by 5 to get 10x + 15y = 35 -------(3)
we multiply (2) by 3 to get 15x - 15y = -33 -------(4)
Now we add (3) and (4) and y is eliminated


Hope this makes it clear for you........

Answer 5

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