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avatar+1836 

Solve the system of equations


If there is a solution, write it as an ordered triple of integers or common fractions in simplest form. For example, if , , and  were a solution, you would enter (1,3/2,-4).
If there is no solution, enter the word "none" as your answer.\(Solve the system of equations \begin{align*} x+y+2z & = 1, \\ -2x +4y + 2z & = 1, \\ y +z &= 1. \end{align*} If there is a solution, write it as an ordered triple of integers or common fractions in simplest form. For example, if $x=1$, $y=\frac64$, and $z=-4$ were a solution, you would enter (1,3/2,-4). If there is no solution, enter the word "none" as your answer. \)

 Jun 2, 2016
 #1
avatar+129852 
+6

x + y + 2z  = 1        (1)

-2x + 4y + 2z = 1     (2)

y + z  = 1                 (3)

 

Multiply (3)  by 2  and rearrange  → 2z = 2 - 2y     (4)

 

Sub (4)  into  (1)    and simplify

 

x + y + [2 - 2 y]  = 1

 

x - y  = -1     (5)

 

Multiply (2) by -1   and add to (1)

 

3x - 3y   = 0     divide both sides by 3

 

x - y  = 0      (6)

 

But.....we have a contradiction  between  (5)  and (6)......x - y  cannot take on two values.....thus.....this system has no solution

 

 

 

cool cool cool

 Jun 2, 2016

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