if x squared plus y squared is equal to 20 and X + Y is equal to 6 then find the value of x cube + y cube
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x^2 + y^2 = 20.
x + y = 6.
(x+y)^2 - 2xy = 20.
36 - 2xy = 20.
-2xy = -18
xy = 8
Now,
x^3 + y^3 = (x+y)(x^2 + y^2 - xy)
x^3 = y^3 = (6)(20-8) = (6)(12) = 72.
Hope it helps!
x + y = 6.
(x+y)^2 - 2xy = 20.
36 - 2xy = 20.
-2xy = -18
xy = 8
Now,
x^3 + y^3 = (x+y)(x^2 + y^2 - xy)
x^3 = y^3 = (6)(20-8) = (6)(12) = 72.
Hope it helps!
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