SSC
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Numerical Ability
Algebra
a+b=10 ; ab=21..........whats the value of a^3 + b^3
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- 370
either a=3 or 7; or b=3 or 7, but the cube of their sum will remain same - 9 years agoHelpfull: Yes(2) No(0)
- We can find that a^2+b^2= 58,
now, a^3+b^3= (a+b)(a^2+b^2-ab)
this gives us, 370 - 9 years agoHelpfull: Yes(0) No(0)
- (a+b)^3=a^3+b^3+3ab(a+b)
also written as a^3+b^3=(a+b)^3-3ab(a+b)
(10)^3-3*21(10)=370
1000-630=370 - 9 years agoHelpfull: Yes(0) No(0)
- 370
either a=3 or 7; or b=3 or 7, but the cube of their sum will remain same - 7 years agoHelpfull: Yes(0) No(0)
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