![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
![](https://blog.hocmai.vn/wp-content/uploads/2017/07/hot.gif)
giải phương trình sau :
a) A = 8( x + 1/x )^2 + 4( x^2 + 1/x^2 )^2 - 4( x^2 + 1/x^2 )( x + 1/x )^2 = ( x + 4 )^2
b) B = [ ( x -1 ) / ( x + 2 ) ]^2 - 4[ (x^2 - 1 ) / ( x^2 - 4 ) ] + 3[ ( x + 1 ) / ( x - 2 ) ] = 0
a) A = 8( x + 1/x )^2 + 4( x^2 + 1/x^2 )^2 - 4( x^2 + 1/x^2 )( x + 1/x )^2 = ( x + 4 )^2
b) B = [ ( x -1 ) / ( x + 2 ) ]^2 - 4[ (x^2 - 1 ) / ( x^2 - 4 ) ] + 3[ ( x + 1 ) / ( x - 2 ) ] = 0