Question

6. (a) If a3 + b3 = 9 and a+b = 3, find ab.​

Answer 1

Step-by-step explanation:

a+b=3

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

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

=>9+3ab*(a+b)=27

=>3ab*(3)=27–9

=>9ab=18

=>ab=2

(1/a)+(1/b)= a+b/ab

=>3/2=1.5

Hence, (1/a)+(1/b) = 1.5