+128406 a^3-2a^2-7a+5, if a=1/(2-3^2) → a = -1/7........so.....
(-1/7)^3 - 2(-1/7)^2 - 7(-1/7) + 5 =
-1/343 - 2/49 + 1 + 5
-1/343 - 14/343 + 6
-15/343 + 6
-15/343 + 2058/343 =
2043 / 343
The value of a^3-2a^2-7a+5, if a=1/(2- root(3)) ,,,the answer is 2,, give me the explanation!!
The value of a^3-2a^2-7a+5, if a=1/(2-3^2)
By saying a=1/ (2 - 3^2) =1/(2 - 9) =1/ - 7. If by 3^2, you mean the"square root of 3", you don't write it 3^2 BUT as "sqrt(3)". Now let us see what we get:
1/(2 - sqrt(3)) = 1/(2 - 1.732....) =1/0.268 =3.7313.... Substitute in your equation:
(3.7313)^3 - (2x3.7313^2) - (7x3.7313) + 5 =
51.949.. - 27.845... - 26.119 + 5 = 3 - The answer would be 3 NOT 2, if you didn't round off.
