without actually calculating the cubes evaluate 14 Cube + 13 cube minus 27 cube
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Use the formula:
a³ + b³ = (a+b)(a²-ab+b²)
a³ - b³ = (a-b)(a²+ab+b²)
14³ + 13³ - 27³
= (14+13)(196 - 182 + 169) - 27³
= 27(183) - 27³
= 4941 - 27³
= 28 + 4913 - 27³
= 28 + 17³ - 27³
= 28 + (17 - 27)(289 + 459 + 729)
= 28 - 10(1477)
= - 14742
a³ + b³ = (a+b)(a²-ab+b²)
a³ - b³ = (a-b)(a²+ab+b²)
14³ + 13³ - 27³
= (14+13)(196 - 182 + 169) - 27³
= 27(183) - 27³
= 4941 - 27³
= 28 + 4913 - 27³
= 28 + 17³ - 27³
= 28 + (17 - 27)(289 + 459 + 729)
= 28 - 10(1477)
= - 14742
ArnaV1901:
bro solve and give!
Done!!
This method is long one. do by short one.
but good attempt.
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