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Question
Solve the following set of simultaneous equation.
2x + y = 5; 3x - y = 5
Solution 1
2x + y = 5
∴ y = 5 - 2x ...(I)
3x - y = 5 ...(II)
Substituting (I) in (II)
3x - y = 5
∴ 3x - (5 - 2x) = 5
∴ 3x - 5 + 2x = 5
∴ 5x = 5 + 5
5x = 10
⇒ `x = 10/5 = 2`
Putting x = 2 in (I) we have,
2 × 2 + y = 5
⇒ 4 + y = 5
⇒ y = 1
(x, y) = (2, 1)
Solution 2
2x + y = 5 ...(1)
3x - y = 5 ...(2)
By adding equations (1) and (2),
2x + y = 5 ...(1)
3x - y = 5 ...(2)
5x = 10
∴ x = `10/5`
∴ x = 2
Substituting x = 2 in equation (1), we get
∴ 2x + y = 5
∴ 2(2) + y = 5
∴ 4 + y = 5
∴ y = 5 - 4
∴ y = 1
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