已知y分之x=3,求y²分之x²+xy的值.通分下列各式:1、x²-2x+1分之1与x²-1分之x;2、x²-4分之x与x²-1分之x-1;3、a-b与a-b分之b
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/27 13:14:43
![已知y分之x=3,求y²分之x²+xy的值.通分下列各式:1、x²-2x+1分之1与x²-1分之x;2、x²-4分之x与x²-1分之x-1;3、a-b与a-b分之b](/uploads/image/z/3911640-24-0.jpg?t=%E5%B7%B2%E7%9F%A5y%E5%88%86%E4%B9%8Bx%3D3%2C%E6%B1%82y%26%23178%3B%E5%88%86%E4%B9%8Bx%26%23178%3B%2Bxy%E7%9A%84%E5%80%BC.%E9%80%9A%E5%88%86%E4%B8%8B%E5%88%97%E5%90%84%E5%BC%8F%EF%BC%9A1%E3%80%81x%26%23178%3B-2x%2B1%E5%88%86%E4%B9%8B1%E4%B8%8Ex%26%23178%3B-1%E5%88%86%E4%B9%8Bx%EF%BC%9B2%E3%80%81x%26%23178%3B-4%E5%88%86%E4%B9%8Bx%E4%B8%8Ex%26%23178%3B-1%E5%88%86%E4%B9%8Bx-1%EF%BC%9B3%E3%80%81a-b%E4%B8%8Ea-b%E5%88%86%E4%B9%8Bb)
已知y分之x=3,求y²分之x²+xy的值.通分下列各式:1、x²-2x+1分之1与x²-1分之x;2、x²-4分之x与x²-1分之x-1;3、a-b与a-b分之b
已知y分之x=3,求y²分之x²+xy的值.通分下列各式:1、x²-2x+1分之1与x²-1分之x;
2、x²-4分之x与x²-1分之x-1;3、a-b与a-b分之b
已知y分之x=3,求y²分之x²+xy的值.通分下列各式:1、x²-2x+1分之1与x²-1分之x;2、x²-4分之x与x²-1分之x-1;3、a-b与a-b分之b
解
x/y=3
∴x=3y
∴(x²+xy)/y²
=(9y²+3y²)/y²
=12y²/y²
=12
最简公分母(x-1)²(x+1)
∴1/(x²-2x+1)=(x+1)/(x-1)²(x+1)
x/(x²-1)=x(x-1)/(x+1)(x-1)²=(x²-x)/(x+1)(x-1)²
最简公分母(x²-4)(x+1)
x/(x²-4)=x(x+1)/(x²-4)(x+1)=(x²+x)/(x²-4)(x+1)
(x-1)/(x²-1)=(x-1)/(x-1)(x+1)=1/(x+1)=(x²-4)/(x²-4)(x+1)
最简公分母为a-b
∴a-b=(a-b)²/(a-b)=(a²-2ab+b²)/(a-b)
b/(a-b)不用变