Question 884332
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1)
d+s=46
320d+260s=13760

1,    1      46
320, 260   13760

divide by 20
2) 
1  ,1  46
16,13 688

3)determinant = -3
d = -90/-3 = 30/1 = 30
s = -48/-3 = 16/1 = 16

1,0,30
0,1,16

4)
inverse matrix
-4.333  0.333
 5.333 -0.333