Question

if (a+b) =4 and ab =3,find the value of a^3+b^3​

Answer 1

a+b=4

a = 4 - b -----(1)

ab = 3

from eq (1)

( 4 - b )b = 3

4b - b^2 = 3

-b^2 + 4b - 3 = 0

b^2 - 4b + 3 = 0

b^2 - b - 3b + 3 = 0

b ( b - 1 ) -3 ( b - 1 ) = 0

( b - 3 ) ( b - 1 ) = 0

b - 3 = 0 b - 1 = 0

b = 3 b = 1

if b = 3 then a = 1

if b = 1 then a = 3

a^3 + b^3 = 1^3 + 3^3

= 1 + 27

= 28

HEY MATE !! HERE IS YOUR ANSWER .

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