Question

if a+b=10,ab=21, find a^3+b^3

Answer 1

Lat a = 7 ,,,,,b= 3
So,
a+b= 10
axb =21


a³ = 7x7x7 = 343
b³ = 3x3x3 =81

Answer 2

a+b=10
ab=21
(a+b)^3= a^3+b^3+3ab(a+b)
 (10)^3 = a^3+b^3 + 3*21(10)
 1000=a^3+b^3+630
 1000-630=a^3+b^3
 370=a^3+b^3

ans = 370
 
 hope its useful...........