Question 343462
You don't necessarily need to solve using matrix methods but it is fastest. 
You could also use substitution or elimination.
[A]={{{(matrix(3,3,30,3,9,35,16,13,200,10,300))}}}
[x]={{{(matrix(3,1,x,y,z))}}}
[b]={{{(matrix(3,1,66,94.5,910))}}}
[A][x]=[b]
[x]=[A]inv[b]
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Find the inverse of [A].
det[A]={{{90750}}}
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[A]inv={{{(1/90750)*(matrix(3,3,4670,-810,-105,-7900,7200,-75,-2850,300,375))}}}
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[x]={{{(matrix(3,1,1.5,1,2))}}}