Math, asked by navinpant123, 10 months ago


if \: x - y = 8 \: and \: xy = 5 \: find \:  {x }^{2} \:  +  {y}^{2}

Answers

Answered by BihariSwag
61

<body bgcolor="r"><font color="white">

Given,

x - y = 8

xy = 5

(x - y)² = 8² = x² + y² - 2xy

64 = x² + y² - 2(5)

x² + y² - 10 = 64

x² +y² = 64 + 10

x² + y² = 74

Answered by umiko28
4

Answer:

{\huge{\overbrace{\underbrace{\purple{your  \: answer:74}}}}}

 <body bgcolor="pink"> \\ \bf\  \:  \: we \: know \: that \\  \:  \:  \boxed{ \implies {(x - y)}^{2} =   {x}^{2}  - 2xy +  {y}^{2} } \\  \\  \:  \:  \:  \bf\ here,  \\   \:  \: \bf\ x - y = 8 \\   \:  \:  \: \bf\ xy = 5 \\   \\  \:  \: \bf\red{now,}  \\  \bf\purple{   \implies  : }{(x - y)}^{2} =   {x}^{2}  - 2xy +  {y}^{2} \\  \\  \bf\purple{  \implies: } {(x - y)}^{2}  + 2xy =  {x}^{2}  +  {y}^{2}  \\  \\ \bf\purple{  \implies: } {(8)}^{2}  + 2 \times 5 =  {x}^{2}  +  {y}^{2}  \\  \\ \bf\purple{  \implies: }64 + 10 =  {x}^{2}  +  {y}^{2}  \\  \\ \bf\purple{  \implies: }74 =  {x}^{2}  +  {y}^{2} \\  \\  \:  \:  \bf\orange{ \boxed {\implies: {x}^{2}  +  {y}^{2}  = 74}}

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