Question

If x=3⅓ + 3⅔, prove that x³-9x-12 = 0​

Answer 1

Answer:

cheap question

Step-by-step explanation:

see the above solution

Answer 2

Step-by-step explanation:

given

x^3 - 9x - 12 =0

or, ( 3^1\3 +3^2\3)^3 - 9 (3^1\3 +3^2\3) -12 =0

or, (3^1\3)^3 + 3 .3^1\3 .3^2\3. ( 3^1\3 +3^2\3) +(3^2/3)^3- 9( 3^1\3 +3^2\3) -12 =0

let ( 3^1\3 +3^2\3) = a

we have,

or, 3 + 3^(1+1\3+2\3)a 3^2 -9a -12=0

or, 3+3^6\3a +9 - 9a -12 =0

or, 12+ 3^2a - 9a -12=0

or 12 -12 +9a - 9a = 0

;. 0 = 0

LHS = RHS proved