①已知x-y=1 求x³y-2x²y²+xy³的值 ②求x²+y²-6x+4y+20的最小值,①已知x-y=1 求x³y-2x²y²+xy³的值②求x²+y²-6x+4y+20的最小值,并求此时x y的值
来源:学生作业帮助网 编辑:作业帮 时间:2024/08/02 03:22:39
![①已知x-y=1 求x³y-2x²y²+xy³的值 ②求x²+y²-6x+4y+20的最小值,①已知x-y=1 求x³y-2x²y²+xy³的值②求x²+y²-6x+4y+20的最小值,并求此时x y的值](/uploads/image/z/3991386-66-6.jpg?t=%E2%91%A0%E5%B7%B2%E7%9F%A5x-y%3D1+%E6%B1%82x%26%23179%3By-2x%26%23178%3By%26%23178%3B%2Bxy%26%23179%3B%E7%9A%84%E5%80%BC+%E2%91%A1%E6%B1%82x%26%23178%3B%2By%26%23178%3B-6x%2B4y%2B20%E7%9A%84%E6%9C%80%E5%B0%8F%E5%80%BC%2C%E2%91%A0%E5%B7%B2%E7%9F%A5x-y%3D1+%E6%B1%82x%26%23179%3By-2x%26%23178%3By%26%23178%3B%2Bxy%26%23179%3B%E7%9A%84%E5%80%BC%E2%91%A1%E6%B1%82x%26%23178%3B%2By%26%23178%3B-6x%2B4y%2B20%E7%9A%84%E6%9C%80%E5%B0%8F%E5%80%BC%2C%E5%B9%B6%E6%B1%82%E6%AD%A4%E6%97%B6x+y%E7%9A%84%E5%80%BC)
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①已知x-y=1 求x³y-2x²y²+xy³的值 ②求x²+y²-6x+4y+20的最小值,①已知x-y=1 求x³y-2x²y²+xy³的值②求x²+y²-6x+4y+20的最小值,并求此时x y的值
①已知x-y=1 求x³y-2x²y²+xy³的值 ②求x²+y²-6x+4y+20的最小值,
①已知x-y=1 求x³y-2x²y²+xy³的值
②求x²+y²-6x+4y+20的最小值,并求此时x y的值
①已知x-y=1 求x³y-2x²y²+xy³的值 ②求x²+y²-6x+4y+20的最小值,①已知x-y=1 求x³y-2x²y²+xy³的值②求x²+y²-6x+4y+20的最小值,并求此时x y的值
① x³y - 2 x²y² + xy³ = xy(x² - 2xy + y²) = xy (x - y)²
如果 x - y = 1
x³y - 2 x²y² + xy³ = xy(x² - 2xy + y²) = xy (1)² = xy
② x² + y² - 6x + 4y + 20 = x² - 6x + 9 + y² + 4y + 4 + 7 = (x - 3)² + (y + 2)² + 7
当x = 3,y = -2 时,代数式取最小值 7