因式分解,9(x-y)²-y²,9a²-4(b+c)²,(x+y+z)²
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/08/12 03:56:38
因式分解,9(x-y)²-y²,9a²-4(b+c)²,(x+y+z)²-(x-y-z)²,
![因式分解,9(x-y)²-y²,9a²-4(b+c)²,(x+y+z)²](/uploads/image/z/18233576-8-6.jpg?t=%E5%9B%A0%E5%BC%8F%E5%88%86%E8%A7%A3%2C9%28x-y%29%26%23178%3B-y%26%23178%3B%2C9a%26%23178%3B-4%28b%EF%BC%8Bc%29%26%23178%3B%2C%EF%BC%88x%EF%BC%8By%EF%BC%8Bz%29%26%23178)
9(x-y)²-y²,
=[3(x-y)]²-y²
=[3(x-y)+y][3(x-y)-y]
=(3x-2y)(3x-4y)
9a²-4(b+c)²,
=(3a)²-[2(b+c)]²
=[3a+2(b+c)][3a-2(b+c)]
=(3a+2b+2c)(3a-2b-2c)
(x+y+z)²-(x-y-z)²
=[(x+y+z)+(x-y-z)][(x+y+z)-(x-y-z)]
=2x(2y+2z)
=4x(y+z)
=[3(x-y)]²-y²
=[3(x-y)+y][3(x-y)-y]
=(3x-2y)(3x-4y)
9a²-4(b+c)²,
=(3a)²-[2(b+c)]²
=[3a+2(b+c)][3a-2(b+c)]
=(3a+2b+2c)(3a-2b-2c)
(x+y+z)²-(x-y-z)²
=[(x+y+z)+(x-y-z)][(x+y+z)-(x-y-z)]
=2x(2y+2z)
=4x(y+z)