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Chelsea12345
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#1
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I'm stuck on this:
Given that x − y = 8, and that xy ≤ 240, find the maximum value of (x + y).
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Chelsea12345
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(Original post by dimapos32)
Since x - y = 8, x = 8 + y.

xy ≤ 240
(y+8)y ≤ 240
y^2 + 8y - 240 ≤ 0

y = [ -20 , 12 ]
max value of y = 12 --> x = 20

So the maximum value is 32 ( x + y = 20 + 12 = 32 )
so what is the maximum value exactly??Could you explain please?
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dimapos32
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(Original post by Chelsea12345)
so what is the maximum value exactly??Could you explain please?
(Original post by dimapos32)
So the maximum value is 32 ( x + y = 20 + 12 = 32 )
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Chelsea12345
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(Original post by dimapos32)
Thankyou!
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