Quantitative Aptitude Ques 1449
Question: If $ m+n=-2, $ then the value of $ m^{3}+n^{3}-6, $ $ mn $ is
Options:
A) $ 8 $
B) $ 4 $
C) $ -8 $
D) $ -4 $
Show Answer
Answer:
Correct Answer: C
Solution:
- Given, $ m+n=-2 $ Now, $ m^{3}+n^{3}-6mn $ $ ={{(m+n)}^{3}}-3mn(m+n)-6mn $ $ [\because a^{3}+b^{3}={{(a+b)}^{3}}-3ab(a+b)] $ $ ={{(-2)}^{3}}-3mn(-2)-6mn $ $ =-,8+6mn-6mn=-,8 $
BETA
