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信息发布者:
$-15$
$\frac{x+2}{x-1}$(答案不唯一)
$\frac{1}{a+b}$
$0.5$
$(a+2b)(a+b)$
$5$或$11$
$m≥ -5$且$m≠ -3$
$\sqrt{13}$
$OC=\frac{\sqrt{5}}{2}EF$
①②③④
解:原式​$=\frac {a^2+2a+1}{a}·\frac {a}{a^2-1}$​
​$=\frac {(a+1)^2}{a}·\frac {a}{(a+1)(a-1)}$​
​$=\frac {a+1}{a-1}$​
解:原式​$=\sqrt {2}+(2-\sqrt {2}+\frac {1}{4})-(2+\sqrt {2}+\frac {1}{4})$​
​$=\sqrt {2}+2-\sqrt {2}+\frac {1}{4}-2-\sqrt {2}-\frac {1}{4}$​
​$=-\sqrt {2}$​