if 9x²+y²=397 and xy=38 ,find the value of 3x+y.
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Answer:
(3x+y) = 25
Step-by-step explanation:
Given 9x^2 + y^2= 397
=> (3x)^2 + (y)^2 = 397
=> (3x+y)^2 - 2 x 3x x y = 397
=> (3x+y)^2 - 6 x (xy) = 397
=> (3x+y)^2 - 6 x 38 = 397
=> (3x+y)^2 - 228 = 397
=> (3x+y)^2 = 397+228 = 625
=> (3x+y) = √625 = 25
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