## solving systems of equations using the elimination meathod

Simplificatation, evaluation, linear equations, linear graphs, linear inequalities, basic word problems, etc.

### solving systems of equations using the elimination meathod

I have been really struggling here.

equations are: 8X-9y=24.5
7y -2x=-8.5 first change this to the other order -2x+7y=-8.5
then eliminate a variable?

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Joined: Thu Jan 08, 2009 10:06 pm

deltadawn wrote:equations are: 8X-9y=24.5 and 7y -2x=-8.5
first change this to the other order -2x+7y=-8.5
then eliminate a variable?

I will guess that you mean "x" and "X" to actually be the same variable. (You can't solve the system otherwise.)

First, read this online lesson to learn the basic idea and methodology for solving a system of equations by "elimination". Then return here and continue....

You have the following:

. . . . .$8x\, -\, 9y\, =\, 24.5$
. . . . .$-2x\, +\, 7y\, =\, -8.5$

Note that the -2(4) = -8, and that (8) + (-8) = 0. Then:

. . . . .$8x\, -\, 9y\, =\, 24.5$
. . . . .$4\left(-2x\, +\, 7y\right)\, =\, 4(-8.5)$

First, multiply out the second equation. Then what happens when you "add down"?

Eliz.

stapel_eliz

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Joined: Mon Dec 08, 2008 4:22 pm