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If x2 – y2 = 16 and x + y > x – y, then which one of the fol
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28 Mar 2019, 13:32
28 Mar 2019, 13:32
Expert Reply
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Question Stats:
76% (01:51) correct
23% (01:28) wrong based on 38 sessions
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If \(x^2 – y^2 = 16\) and \(x + y > x – y\), then which one of the following could x – y equal?
(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
(A) 3
(B) 4
(C) 5
(D) 6
(E) 7
Re: If x2 – y2 = 16 and x + y > x – y, then which one of the fol
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30 Mar 2019, 01:53
30 Mar 2019, 01:53
Can you explain?
Re: If x2 – y2 = 16 and x + y > x – y, then which one of the fol
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30 Mar 2019, 05:50
30 Mar 2019, 05:50
1
Expert Reply
\((x^2 - y^2 ) = 16\)
So
\((x+y)(x-y) > (x-y)(x-y)\)
\(x^2 - y^2 > (x-y)^2\)
\(16 > (x-y)^2\)
\(\sqrt{16} > \sqrt{(x-y)^2}\)
\(4 > x-y\)
So x-y must be 3
So
\((x+y)(x-y) > (x-y)(x-y)\)
\(x^2 - y^2 > (x-y)^2\)
\(16 > (x-y)^2\)
\(\sqrt{16} > \sqrt{(x-y)^2}\)
\(4 > x-y\)
So x-y must be 3
