请帮我解答以下两道求x、y的题,
来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/07/17 05:00:32
请帮我解答以下两道求x、y的题,
![](http://img.wesiedu.com/upload/e/4f/e4f28bc49d40affb069786d6b1d9d287.jpg)
![](http://img.wesiedu.com/upload/e/4f/e4f28bc49d40affb069786d6b1d9d287.jpg)
2x^2+x-21=(2x+7)(x-3)
13/((2x+7)(x-3))=(6(2x+7)-(x^2-9))/((x-3)(x+3)(2x+7))
13(x+3)=6(2x+7)-(x^2-9)
x^2-x-12=0
(x-3)(x+4)=0
x=3,or x=-4
--------------------------------
25 x^2 y^2 =100 (x+y)^2
=4(x^2+y^2)^2
x^2-y^2=(x+y)(x-y)
(x^2+y^2)^2= (5(x+y))^2
(X^2+y^2+(5(x+y)) (x^2+y^2-5(x+y))=0
(X^2+y^2+(5(x+y))=0------------------(1)
(x^2+y^2-5(x+y))=0---------------------(2)
(1)-(2)
x+y=0
y=-x
13/((2x+7)(x-3))=(6(2x+7)-(x^2-9))/((x-3)(x+3)(2x+7))
13(x+3)=6(2x+7)-(x^2-9)
x^2-x-12=0
(x-3)(x+4)=0
x=3,or x=-4
--------------------------------
25 x^2 y^2 =100 (x+y)^2
=4(x^2+y^2)^2
x^2-y^2=(x+y)(x-y)
(x^2+y^2)^2= (5(x+y))^2
(X^2+y^2+(5(x+y)) (x^2+y^2-5(x+y))=0
(X^2+y^2+(5(x+y))=0------------------(1)
(x^2+y^2-5(x+y))=0---------------------(2)
(1)-(2)
x+y=0
y=-x