Question

If a+b=3 and ab =2 find the value of a^3+b^3

Answer 1

Answer:

your answer attached in the photo

Answer 2

Answer:

a + b = 3

Cube on both sides-

Using ( x + y )^3 = x^3 + y^3 + 3xy( x + y )

= > ( a + b )^3 = 3^3

= > a^3 + b^3 + 3ab( a + b ) = 27

ab = 2 and a + b = 3

= > a^3 + b^3 + 3(2)(3) = 27

= > a^3 + b^3 + 18 = 27

= > a^3 + b^3 = 27 - 18

= > a^3 + b^3 = 9

Hence a^3 + b^3 = 9