分解因式(1)x²(x-y)+(y-x)(2)(x-3)(x+2)+4/25求值 (1)x/x+1 ÷ (x - x/1)其中x=根号2+ 1 (2)解不等式组①2x-3≥1②2/x-1 +2≥-x(ps:2/x-1+2≥-x是 x-1 )——+2≥-x 是这样的,2

问题描述:

分解因式(1)x²(x-y)+(y-x)(2)(x-3)(x+2)+4/25
求值 (1)x/x+1 ÷ (x - x/1)其中x=根号2+ 1 (2)解不等式组①2x-3≥1②2/x-1 +2≥-x
(ps:2/x-1+2≥-x是 x-1 )
——+2≥-x 是这样的,
2

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x"( x - y ) + ( y - x )
= x"( x - y ) - ( x - y )
= ( x - y )( x" - 1 )
= ( x - y )( x - 1 )( x + 1 )
( x - 3 )( x + 2 ) + 25/4
= x" + 2x - 3x - 6 + 6 + 1/4
= x" - x + 1/4
= x" - ( 2 / 2 )x + ( 1/2 )"
= ( x - 1/2 )"
[ ( x + 1 )/x ] / ( x - 1/x )
= [ ( 1/x )( x + 1 ) ] / [ ( 1/x )( x" - 1 ) ]
= ( x + 1 ) / [ ( x + 1 )( x - 1 ) ]
= 1 / ( x - 1 )
= 1 / [ ( √2 + 1 ) - 1 ]
= 1 / ( √2 )
= √2 / 2
2x - 3 >= 1
2x >= 4
x >= 2
( x - 1 )/2 + 2 >= -x
x - 1 + 4 >= -2x
3x + 3 >= 0
3x >= -3
x >= -1
注意:
分子、分母如果写在同一行,
就应该是分子除以分母,如【 分子 / 分母 】