Expert: Sherman D. - 11/28/2006

Question
[8 7] X= [3 -6]
1 1      -2 9

Answer
if you are saying that 8,7,1,1 are in one box and 3,-6,-2,9 are in the second box, then

8,7,1,1 * x = 3,-6,-2,9
x = (3,-6,-2,9) / (8,7,1,1)
x = (8,7,1,1)^-1 * (3,-6,-2,9)

(1,-7) (3,-6)
(-1,8) (-2,9)

|((1*3) + (-7 * -2)) , ((1 * -6) + (-7 * 9))|
|((-1 * 3) + (8 * -2)) , ((-1 * -6) + (8 * 9))|

|(3 + 14),(-6 + -63)|
|(-3 - 16),(6 + 72)|

x =
|17,-69|
|-19,78|

If the look doesn't turn out right, then sorry, its just the way this website works. It left aligns everything.

If you go to www.quickmath.com, click on Arithmetic, then find the inverse of (8,7,1,1), then click on the Matrix 1 * Matrix 2, and type in the inverse of (8,7,1,1) and type in (3,-6,-2,9), it will give you the same values, but it won't work it out for you.