分解因式 要步骤
1.7x^2-632.a^3-a3.3a^2-3b^24.y^2-9(x+y)^25..(x+y)的平方-16(x-y)的平方6.a方(a-b)方-b方(a+b)方7.(...
1. 7x^2-63
2. a^3-a
3. 3a^2-3b^2
4. y^2-9(x+y)^2
5. .(x+y)的平方-16(x-y)的平方
6. a方(a-b)方-b方(a+b)方
7.(x+y+z)方-(x-y-z)方
8.(x+y)方-14(x+y)+49
在线等啊 展开
2. a^3-a
3. 3a^2-3b^2
4. y^2-9(x+y)^2
5. .(x+y)的平方-16(x-y)的平方
6. a方(a-b)方-b方(a+b)方
7.(x+y+z)方-(x-y-z)方
8.(x+y)方-14(x+y)+49
在线等啊 展开
1个回答
展开全部
1. 7x^2-63
=7(x^2-9)
=7(x-3)(x+3)
2. a^3-a
=a(a^2-1)
=a(a+1)(a-1)
3. 3a^2-3b^2
=3(a^2-b^2)
=3(a+b)(a-b)
4. y^2-9(x+y)^2
=[y-3(x+y)][y+3(x+y)]
=(y-3x-3y)(y+3x+3y)
=(-3x-2y)(3x+4y)
=-(3x+2y)(3x+4y)
5. .(x+y)^2-16(x-y)^2
=[(x+y)-4(x-y)][(x+y)+4(x-y)]
=(x+y-4x+4y)(x+y+4x-4y)
=(5y-3x)(5x-3y)
6. a^2(a-b)^2-b^2(a+b)^2
=[a(a-b)-b(a+b)][a(a-b)+b(a+b)]
=(a^2-ab-ab-b^2)(a^2-ab+ab+b^2)
=(a^2-2ab-b^2)(a^2+b^2)
7.(x+y+z)^2-(x-y-z)^2
=[(x+y+z)-(x-y-z)][(x+y+z)+(x-y-z)]
=(x+y+z-x+y+z)(x+y+z+x-y-z)
=(2y+2z)*2x
=4x(y+z)
8.(x+y)^2-14(x+y)+49
=(x+y-7)^2
=7(x^2-9)
=7(x-3)(x+3)
2. a^3-a
=a(a^2-1)
=a(a+1)(a-1)
3. 3a^2-3b^2
=3(a^2-b^2)
=3(a+b)(a-b)
4. y^2-9(x+y)^2
=[y-3(x+y)][y+3(x+y)]
=(y-3x-3y)(y+3x+3y)
=(-3x-2y)(3x+4y)
=-(3x+2y)(3x+4y)
5. .(x+y)^2-16(x-y)^2
=[(x+y)-4(x-y)][(x+y)+4(x-y)]
=(x+y-4x+4y)(x+y+4x-4y)
=(5y-3x)(5x-3y)
6. a^2(a-b)^2-b^2(a+b)^2
=[a(a-b)-b(a+b)][a(a-b)+b(a+b)]
=(a^2-ab-ab-b^2)(a^2-ab+ab+b^2)
=(a^2-2ab-b^2)(a^2+b^2)
7.(x+y+z)^2-(x-y-z)^2
=[(x+y+z)-(x-y-z)][(x+y+z)+(x-y-z)]
=(x+y+z-x+y+z)(x+y+z+x-y-z)
=(2y+2z)*2x
=4x(y+z)
8.(x+y)^2-14(x+y)+49
=(x+y-7)^2
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