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$x^3 + y^3 = 35$ and $x + y = 5$, then the value of ($\frac{1}{x} + \frac{1}{y}$) is
$x^3 + y^3 = 35$ and $x + y = 5$, then the value of ($\frac{1}{x} + \frac{1}{y}$) is
1). 4/7
2). 3/8
3). 5/6
4). 3/5
1). 4/7
2). 3/8
3). 5/6
4). 3/5
This Question has 1 answers.
x3 + y3 = 35
\n\n⇒ $(x + y) (x2 - xy + y2) = 35
\n\n⇒ $5(x2 - xy + y2) = 35
\n\n⇒ $x2 - xy + y2 = 7
\n\n⇒ $(x + y)2 - 3xy = 7
\n\n⇒ $25 - 3xy = 7 (? x + y = 5)
\n\n⇒ $3xy = 18
\n\n⇒ $xy = 6
\n∴ 1/x + 1/y = (x + y)/xy = 5/6Similar Questions
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