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=///=
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![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=///=](/uploads/image/z/2541711-39-1.jpg?t=%E5%88%86%E8%A7%A3%E5%9B%A0%E5%BC%8F%EF%BC%9A%281%29.%28x%5E2%2B2x%2B3%29%28x%5E2%2B2x%2B2%29-30+%282%29.x%5E2%2B2xy%2By%5E2-4x-7y-12+%283%29.x-y-x%5E2%2B2xy-y%5E2%2B2%284%29.%E8%A7%A3%E6%96%B9%E7%A8%8B%EF%BC%9A3x%5E2-11x%2B10%3D0LZ%E4%B8%8D%E6%89%8D...%E6%B1%82%E8%A7%A3%3D%2F%2F%2F%3D)
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