Question

3 If x+y=5 and xy=6 find the value of xcube+ycube
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Answer 1

Answer:

The value of $x^3+y^3=35$

Step-by-step explanation:

Given,

         $x+y =5\\ xy =6$

we can use the identity,

                 $(x+y)^3 =x^3 + y^3+3xy(x+y)$

Putting the value of $(x+y) \hspace {2mm} and \hspace {2mm} xy ,$ in the algebraic expression ,we get

$5^3=x^3+y^3+3\cdot 6\cdot 5\\ \\ 125=x^3+y^3+90\\ \\ x^3+y^3=125-90\\ \\ x^3+y^3=35$