作业帮分解因式：(1).(x^2+2x+3)(x^2+2x+2)-30 (2).x^2+2xy+y^2-4x-7y-12 (3).x-y-x^2+2xy-y^2+2(4).解方程：3x^2-11x+10=0LZ不才...求解=///=
来源：学生作业帮助网 编辑：作业帮 时间：2024/05/04 11:22:15
分解因式：(1).(x^2+2x+3)(x^2+2x+2)-30 (2).x^2+2xy+y^2-4x-7y-12 (3).x-y-x^2+2xy-y^2+2(4).解方程：3x^2-11x+10=0LZ不才...求解=///=
分解因式：(1).(x^2+2x+3)(x^2+2x+2)-30 (2).x^2+2xy+y^2-4x-7y-12 (3).x-y-x^2+2xy-y^2+2
(4).解方程：3x^2-11x+10=0
LZ不才...求解=///=
分解因式：(1).(x^2+2x+3)(x^2+2x+2)-30 (2).x^2+2xy+y^2-4x-7y-12 (3).x-y-x^2+2xy-y^2+2(4).解方程：3x^2-11x+10=0LZ不才...求解=///=
1、原式=[(x²＋2x)＋3]×[(x²＋2x)＋2]－30
=(x²＋2x)²＋5(x²＋2x)＋6－30
=(x²＋2x)²＋5(x²＋2x)－24
=[(x²＋2x)＋8]×[(x²＋2x)－3]
=(x＋3)(x－1)(x²＋2x＋8)
2、原式=(x＋y)²－4(x＋y)－12=[(x＋y)＋2]×[(x＋y)－6]=(x＋y＋2)(x＋y－6)
3、原式=－[(x－y)²－(x－y)－2]=－(x－y＋1)(x－y－2)
4、3x²－11x＋10=0
(3x－5)(x－2)=0
x=5/3或x=2
(x^2+2x+3)(x^2+2x+2)-30
=[(x^2+2x+2)+1](x^2+2x+2)-30
=(x^2+2x+2)^2+(x^2+2x+2)-30
=(x^2+2x+2+6)(x^2+2x+2-5)
=(x^2+2x+8)(x^2+2x-3)
=(x^2+2x+8)(x+3)(x-1)
x^2+2xy+y^2-4x-4y-12
...
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(x^2+2x+3)(x^2+2x+2)-30
=[(x^2+2x+2)+1](x^2+2x+2)-30
=(x^2+2x+2)^2+(x^2+2x+2)-30
=(x^2+2x+2+6)(x^2+2x+2-5)
=(x^2+2x+8)(x^2+2x-3)
=(x^2+2x+8)(x+3)(x-1)
x^2+2xy+y^2-4x-4y-12
=(x+y)^2-4(x+y)-12
=(x+y-6)(x+y+2)
x-y-x^2+2xy-y^2+2
=-(x^2-2xy+y^2-x+y-2)
=-[(x-y)^2-(x-y)-2]
=-(x-y-2)(x-y+1)
3x^2-11x+10=0
(3x-5)(x-2)=0
x=5/3或x=2
收起
自己算啊