Q14 without actually calcculating the cubes, find the value of each of the following: (-12)×(-12)×(-12) (this is cube) +(7)3+*(5)3

Asked by Diwaker.rathore | 13th Apr, 2019, 03:34: PM

Expert Answer:

begin mathsize 16px style open parentheses negative 12 close parentheses cubed plus open parentheses 7 close parentheses cubed plus open parentheses 5 close parentheses cubed
We space know space that comma
straight x cubed space plus space straight y cubed space plus straight z cubed space equals space 3 xyz space plus space left parenthesis straight x space plus space straight y space plus space straight z right parenthesis left parenthesis straight x squared plus space straight y squared plus space straight z squared minus space xy space minus space yz space minus space zx right parenthesis
Here space straight x space equals space minus 12 comma space straight y space equals space 7 comma space straight z space equals space 5 comma
rightwards double arrow open parentheses negative 12 close parentheses cubed plus open parentheses 7 close parentheses cubed plus open parentheses 5 close parentheses cubed
equals space 3 left parenthesis negative 12 right parenthesis left parenthesis 7 right parenthesis left parenthesis 5 right parenthesis space plus space left parenthesis negative 12 space plus space 7 plus space 5 right parenthesis open square brackets open parentheses negative 12 close parentheses squared plus space open parentheses 7 close parentheses squared plus space open parentheses 5 close parentheses squared space minus left parenthesis negative 12 space cross times space 7 right parenthesis space minus space left parenthesis 7 space cross times space 5 right parenthesis space minus space left parenthesis 5 cross times negative 12 right parenthesis close square brackets
equals space minus 1260 end style

Answered by Yasmeen Khan | 14th Apr, 2019, 03:38: PM

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