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Question
By equating coefficients of variables, solve the following equation.
5x + 7y = 17 ; 3x - 2y = 4
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Solution
5x + 7y = 17 ...(I)
3x - 2y = 4 ...(II)
Multiply (I) with 3 and (II) with 5
15x + 21y = 51 ...(III)
15x - 10y = 20 ...(IV)
Subtracting (IV) from (III) we get,
15x + 21y = 51
15x - 10y = 20
- + -
31y = 31
⇒ y = 1
Putting this value of y in (I) we get
∴ 5x + 7y = 17
5x + 7 × 1 = 17
⇒ 5x = 10
⇒ x = 2
Thus, x = 2, y = 1
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