if x+y=12 and  xy=14 :find the value of xsquare +y square

 x+y        =12

xy           =14; x2+y2  =?

using the identity (a+b)2  =a2+b2 +2ab

(x+y)2                       =x2 +y2 +2xy

(12)2                         =x2+y2+2(14)

144                           =x2+y2+28

144-28                    =x2+y2

therefore  x2+ y2  =116

  • 59

we know(x+y)2= x2+y2+ 2xy

and(x+y)2 -2xy =x2+y2

so(12)2=x2+y2+2(14)

144 =x2+y2+28

144-28 =x2+y2

sox2+ y2=116

  • 16

we know(x+y)2= x2+y2+ 2xy

and(x+y)2 -2xy =x2+y2

so(12)2=x2+y2+2(14)

144 =x2+y2+28

144-28 =x2+y2

sox2+ y2=116

  • 19
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