If a-b=6 and ab=20, find a3(cube) - b3(cube)
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(a-b) = 6
Cubing both sides ;
(a-b) ^3 = 6^3
=) a^3 - b^3 - 3ab(a-b) = 216
=) a^3 - b^3 - 3*20*6 = 216
=) a^3 - b^3 - 360 = 216
=) a^3 - b^3 = 216+360
=) a^3 - b^3 = 576
Hope it's helpful to u.
Cubing both sides ;
(a-b) ^3 = 6^3
=) a^3 - b^3 - 3ab(a-b) = 216
=) a^3 - b^3 - 3*20*6 = 216
=) a^3 - b^3 - 360 = 216
=) a^3 - b^3 = 216+360
=) a^3 - b^3 = 576
Hope it's helpful to u.
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