To solve the equations
:
2x+3y+z = 5...(1) x+3y+5z = 8....(2) 4x+y+z =
10.....(3)
(3)-(1): (4x+y+z) - (2x+3y+z) = 10-5 =
5
2x-2y = 5...(4).
5(3)-(2) :
5(4x+y+z) -(x+3y+5z)= 5*10 - 8 = 42
19x-2y =
42...(5).
(4)+(5): 21x = 42+5 =
47
x = 47/21. Put this value of x in
eq(4):
2(47/21) -2y = 5. So 2y = 94/21 -5 = -11/21. Or y =
-11/42.
Therefore substitute x = 47/21 , y = -11/42 in eq
(1), that is , in 2x+3y+z = 5:
2(47/21)+3(-11/42)+z = 5.
Or z = 5-94/21 +33/42 = (210-188+33)/42.
z =
55/42
Therefore x = 47/22 , y = -11/42 and z =
55/42.
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