Question

2.先化简,再求值: x²+6x+9/x²-9·x²-3x/x+3 ,其中x=2？

求大神解答(๑•́ ㉨ •̀๑)

Answer 1

如图：

Answer 2

[(x^2+6x+9)/(x^2-9)][(x^2-3x)/(x+3)]
={ (x+3)^2/[(x-3)(x+3)] }.[x(x-3)/(x+3)]
=x
x=2
[(x^2+6x+9)/(x^2-9)][(x^2-3x)/(x+3)]
=2

Answer 3

你写的题目不明确，两个分数线。分数线的分子管到哪里？分母呢？你最好拍原题图发来。

Answer 4

[(x^2+6x+9)/(x^2-9)][(x^2-3x)/(x+3)]
={ (x+3)^2/[(x-3)(x+3)] }.[x(x-3)/(x+3)]
=1/x
x=2
[(x^2+6x+9)/(x^2-9)][(x^2-3x)/(x+3)]
=1/2

Answer 5

已知：X＝2
（X^2+6X+9）／（X^2−9）·（X^2−3X）／（X+3）
＝（X+3）^2/（X+3）（X－3）·X（X－3）／（X+3）
＝X＝2