Question 302770
Are these linear systems of functions of x ({{{x}}}, {{{x^2}}}, and {{{x^3}}})? 
{{{ graph( 300, 300, -10, 10, -10, 10, x^1+x^2+x^3, 2x^1-x^2-x^3+3, x^1-x^2+x^3) }}}
If so, it doesn't look like there is a solution (no common intersection point for all three graphs).
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Or are these {{{x1}}}, {{{x2}}}, and {{{x3}}}, three variables? 

[A]={{{(matrix(3,3,1,1,1,2,-1,-1,1,-1,1))}}}
[x]={{{(matrix(3,1,x1,x2,x3))}}}
[b]={{{(matrix(3,1,0,-3,0))}}}
Then 
[A][x]=[b]
[x]=[A]inv[b]
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det[A]={{{-6}}}
[A]inv={{{-(1/6)*(matrix(3,3,-2,-2,0,-3,0,3,-1,0,-3))}}}
[x]={{{(matrix(3,1,-1,0,1))}}}
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{{{x1=-1}}}
{{{x2=0}}}
{{{x3=1}}}