因式分解 －（x＋2）²＋16（x-1）² -16x的四次方＋x²y² a²-b²＋a＋b

a" - b" + a + b
= ( a - b )( a + b ) + ( a + b )
= ( a + b )( a - b + 1 )
- ( x + 2 )" + 16( x - 1 )"
= 16( x - 1 )" - ( x + 2 )"
= [ 4( x - 1 ) - ( x + 2 ) ][ 4( x - 1 ) + ( x + 2 ) ]
= ( 4x - 4 - x - 2 )( 4x - 4 + x + 2 )
= ( 3x - 6 )( 5x - 2 )
= 3( x - 2 )( 5x - 2 )
- 16(x^4) + x"y"
= x"( y" - 16x" )
= x"( y - 4x )( y + 4x )