View Full Version : Syst. of Eqns: -6x+2y+12z = -90, -4x+y+4z = -40, -3z = 15
I need help with 2 math problems. they are Systems of Equations.
-6x + 2y + 12z = -90
-4x + y + 4z = -40
-3z = 15
6x + 6y - 2z = -410
-2x - y - 3z = 182
x + 6y + 6z = -335
10-14-2008, 04:32 PM
On the first exercise, solve the third equation for z.
Substitute the result for z in each of the first two equations.
You now have a system of two equations involving two variables, which can be solved using a variety of methods.
On the second exercise, group the first two equations together AND group the last two equations together.
You can use the elimination method on each pair of equations to remove the same variable from each group. These two results will form a system of two equations involving two variables, which can be solved using a variety of methods.
If you're not sure how to do any of this, then please tell us which methods of solving systems of equations with which you are familiar.
Once we know which method to discuss, we can be more specific.
If you're able to get started, but you get stuck, then please post whatever work you've been able to accomplish (right or wrong), and we'll go from there.
There are plenty of examples of methods on the Internet; try a Google search on keywords like "solve system two equations".
~ Mark :)
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