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Question
If 2x + y = 23 and 4x - y = 19 : find the value of x - 3y and 5y - 2x.
Solution
2x + y = 23 ........(1)
4x - y = 19 ........(2)
Adding (1) and (2),
6x = 42
⇒ x = 7
∴ y = 23 - 2x
= 23 - 14
= 9
∴ x - 3y
= 7 - 3(9)
= 7 - 27
= -20
5y - 2x
= 5(9) - 2(7)
= 45 - 14
= 31.
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