Đáp án:
Giải thích các bước giải:
`( 3x + 1 )/(( x - 1 )^2 ) - 1/( x + 1 ) + ( x + 3 )/( 1 - x^2 )`
`= (( 3x + 1 )( x + 1 ))/(( x - 1 )^2( x + 1 )) - (( x - 1 )^2)/(( x + 1 )( x - 1 )^2 ) - ( x + 3 )/( x^2 - 1 )`
`= (3x^2 + 4x + 1)/(( x - 1 )^2( x + 1 )) - (x^2 - 2x + 1)/(( x + 1 )( x - 1 )^2 ) - (x + 3)/((x - 1)(x + 1))`
`= ( 3x^2 + 4x + 1 )/(( x - 1 )^2( x + 1 )) - (x^2 - 2x + 1)/(( x + 1 )( x - 1 )^2 ) - (( x + 3 )( x - 1 ))/(( x - 1 )^2( x + 1 ))`
`= ( 3x^2 + 4x + 1 )/(( x - 1 )^2( x + 1 )) - (x^2 - 2x + 1)/(( x + 1 )( x - 1 )^2 ) - ( x^2 + 2x - 3 )/(( x - 1 )^2( x + 1 ))`
`= ( x^2 + 4x + 3 )/(( x - 1 )^2( x + 1 ))`
`= (( x + 1 )( x + 3 ))/(( x - 1 )^2( x + 1 ))`
`= ( x + 3 )/(( x - 1 )^2 )`
