x+y-z+w = 10--------(1)
x+3y-4z+5w=26------(2)
x+4y-7z+7w = 37-------(3)
x+2y-3z+6w = 22--------(4)
Subtract equation (1) from (2)
x+3y-4z+5w - (x+y-z+w) = 26 - 10
2y + -3z - 4w = 16-----------------------------(5)
Subtract equation (1) from (3)
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