------- eq (i)
------- eq (ii)
------- eq (iii)
x + 3y + z = 3 ----- Multiplying eq (i) by LCD, 6 ------- eq (iv)
x + y + z = 5 ----- eq (ii)
2x + 3y + z = 6 ----- Multiplying eq (iii) by LCD, 6 ----- eq (v)
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2y = - 2 ----- Subtracting eq (ii) from eq (iv)
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----- Subtracting eq (v) from eq (iv)
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3 + - 1 + z = 5 ----- Substituting 3 for x, and - 1 for y in eq (ii)