+0  
 
0
145
3
avatar

The value of a^3-2a^2-7a+5, if a=1/(2-3^2)

Guest Mar 7, 2017
 #1
avatar+87334 
0

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

 

 

cool cool cool

CPhill  Mar 7, 2017
 #2
avatar
0

The value of a^3-2a^2-7a+5, if a=1/(2-  root(3))  ,,,the answer is 2,, give me the explanation!! 

Guest Mar 7, 2017
 #3
avatar
0

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. 

Guest Mar 7, 2017

11 Online Users

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.