Question

if a + b is 10 a b is 21 then what is a cube plus b cube​

Answer 1

I hope it may help you thank you for your question ....

Answer 2

Heya!

a × b = 21

a + b = 10 ... Equation i

Cubing on both sides in Equation i we have

( a + b )³ = (10)³

a³ + b³ + 3ab ( a + b ) = 1000

Becoz ( x + y )³ = x³ + y³ + 3xy ( x + y )

a³ + b³ + 3 × 21 ( 10 ) = 1000

a³ + b³ = 1000 - 630

a³ + b³ = 370

So,

a³ + b³ = 370