SSC
Government Jobs Exams
Numerical Ability
Algebra
a+b=10 ; ab=21..........whats the value of a^3 + b^3
Read Solution (Total 4)
-
- 370
either a=3 or 7; or b=3 or 7, but the cube of their sum will remain same - 8 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 - 8 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 - 8 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)
SSC Other Question