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Question
If 2x + y = 23 and 4x - y = 19; find the values of x - 3y and 5y - 2x.
Solution
2x + y = 23 ...(1)
4x - y = 19 ...(2)
Adding equation (1) and (2) we get,
2x + y = 23
+ 4x - y = 19
6x = 42
x = 7
From (1)
2x + y = 23
⇒ 2(7) + y = 23
⇒ 14 + y = 23
⇒ y = 23 - 14
y = 9
∴ x - 3y = 7 - 3(9) = -20
and 5y - 2x = 5(9) - 2(7) = 45 - 14 = 31.
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