作业帮①.x2-2x-1 ②.4(x-y+1)+y(y-2x) ③.3x2+5xy-2y2+x+9y-4 ④.x2-5x+3 ⑤.3x2+4xy-y2 在实数范围内因式分解字母后面的 2 是平方的意思
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①.x2-2x-1 ②.4(x-y+1)+y(y-2x) ③.3x2+5xy-2y2+x+9y-4 ④.x2-5x+3 ⑤.3x2+4xy-y2 在实数范围内因式分解字母后面的 2 是平方的意思
①.x2-2x-1 ②.4(x-y+1)+y(y-2x) ③.3x2+5xy-2y2+x+9y-4 ④.x2-5x+3 ⑤.3x2+4xy-y2 在实数范围内因式分解
字母后面的 2 是平方的意思
①.x2-2x-1 ②.4(x-y+1)+y(y-2x) ③.3x2+5xy-2y2+x+9y-4 ④.x2-5x+3 ⑤.3x2+4xy-y2 在实数范围内因式分解字母后面的 2 是平方的意思
x" - 2x - 1
= x" - 2x + 1 - 2
= ( x - 1 )" - (√2)"
= ( x - 1 - √2 )( x - 1 + √2 )
4( x - y + 1 ) + y( y - 2x )
= 4x - 4y + 4 + y" - 2xy
= ( 4x - 2xy ) + ( 4 - 4y + y" )
= 2x( 2 - y ) + ( 2 - y )"
= ( 2 - y )( 2x + 2 - y )
= ( 2x - y + 2 )( 2 - y )
3x" + 5xy - 2y" + x + 9y - 4
= 3x" + 6xy + 3y" - xy - 5y" + x + 9y - 4
= 3( x" + 2xy + y" ) - xy - y" - 4y" + ( x + y ) + 8y - 4
= 3( x + y )" - y( x + y ) + ( x + y ) - 4y" + 8y - 4
= 3( x + y )" - ( x + y )( y - 1 ) - 4( y" - 2y + 1 )
= 3( x + y )" + 3( x + y )( y - 1 ) - 4( x + y )( y - 1 ) - 4( y - 1 )"
= 3( x + y )( x + y + y - 1 ) - 4( y - 1 )( x + y + y - 1 )
= ( x + 2y - 1 )( 3x + 3y - 4y + 4 )
= ( x + 2y - 1 )( 3x - y + 4 )
x" - 5x + 3
= ( 1/4 )( 4x" - 20x + 12 )
= ( 1/4 )[ ( 2x )" - 10( 2x ) + 5" - 25 + 12 ]
= ( 1/4 )[ ( 2x - 5 )" - 13 ]
= ( 1/4 )[ ( 2x - 5 )" - ( √13 )" ]
= ( 1/4 )( 2x - 5 - √13 )( 2x - 5 + √13 )
3x" + 4xy - y"
= 3x" + 4x" - 4x" + 4xy - y"
= 7x" - [ 4x" - 4xy + y" ]
= [ (√7)x ]" - ( 2x - y )"
= [ (√7)x + 2x - y ][ (√7)x - 2x + y ]