4-Variable Systems of EquationsDate: 12/10/2002 at 21:50:21 From: Aaron Igdalsky Subject: Solving 4 Variable Systems of Equations I am stumped! 2w-x+5y+z=-3 3w+2x+2y-6z=-32 w+3x+3y-z=-47 5w-2x-3y+3z=49 Date: 12/11/2002 at 10:50:15 From: Doctor Ian Subject: Re: Solving 4 Variable Systems of Equations Hi Aaron, Do you remember how to solve a system with two equations and two variables by substitution? This works the same way, but has more steps. Suppose we take the first equation, and solve it for z: z = -2w + x - 5y - 3 Now we can replace z in the other equations to get 3w + 2x + 2y - 6(-2w + x - 5y - 3) = -32 w + 3x + 3y - (-2w + x - 5y - 3) = -47 5w - 2x - 3y + 3(-2w + x - 5y - 3) = 49 Simplify these, and you'll end up with three equations and three variables. Try the same trick again with another variable, and you'll have two equations in two variables. Is this enough to get started? - Doctor Ian, The Math Forum http://mathforum.org/dr.math/ |
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