Question 173807
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We must find the inverse of matrix A in order to solve for x
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A= [6,5]    
   [4,-2]
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take terms {{{a[11]}}}and {{{a[22]}}} and switch their positions. This is simply switching the elements on the main diagonal 
 
take terms {{{a[12]}}}and {{{a[21]}}} and change those numbers to their opposites keeping there positions.

{{{(matrix(2,2,-2,-5,-4,6))}}}-revised matrix
:now we find the determinant of this matrix
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product of the main diagonal minus the product of the off diagonal
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{{{-12-20=-32}}}
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we take that result and divide every element in the revised matrix  and the result is our inverse matrix
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{{{(matrix(2,2,1/16,5/32,1/8,-3/16))}}}
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Now we have to multiply each side of the equation AX=B by the matrix A's inverse
On the left hand side we will end up with the indentity matrix multiplied by X which is equal to just X. So {{{X=A^-1(B)}}}
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A= [6,5]    B= [18,49]
   [4,-2]      [-20,6]
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so 
X={{{(matrix(2,2,1/16,5/32,1/8,-3/16))}}}*{{{(matrix(2,2,18,49,-20,6))}}}---->
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={{{(matrix(2,2,-2,4,6,5))}}}
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2) I will leave the details and steps of # 2 to you 
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the answer is {{{(matrix(2,2,2,-2,1,-1))}}}