Question

If a+b=10 a^2+ b^2=58 find a^3+b^3

Plz with steps

Answer 1

a³ + b³ = (a + b) (a² - ab + b²)
= 10 (58 - ab)
But (a + b)² = a² + 2ab + b² = 58+2ab
also (a+b)2=10² = 100 since a+b=10
58+2ab=100
=> 2ab =100-58=42
=> ab = 21
=>a³ + b³ = (a + b) (a² - ab + b²)
= 10 (58 - ab)
=10*(58 - 21) = 370

Answer 2

look this. very simple logic !!

a + b = 10

hence the number is 7 and 3



a² + b² = 58


check

7² + 3² = 58


now


a³+ b³= 7³ + 3³



=> 343+ 27


= 370


hope it help you !!

thanks !!