如果A/(a^2-b^2) b/(a-b)=(a-b)/(a b),则A等于?
如果A/(a^2-b^2)+b/(a-b)=(a-b)/(a+b),则A等于?
移项:A/(a^2-b^2)=(a-b)/(a+b)-b/(a-b), 右侧通分:A/(a^2-b^2)=[(a-b)^2-b(a+b)]/(a^2-b^2), 两边同乘(a^2-b^2)并打开右侧括号:A=a^2-3ab.
A=a^2-3ab
[A/(a^2-b^2)]+[b/(a-b)]=(a-b)/(a+b), [A/(a+b)(a-b)]+[b/(a-b)]=(a-b)/(a+b), [A+b(a+b)]/(a+b)(a-b)=(a-b)/(a+b), [A+b(a+b)]=(a-b)^2 A+ab+b^2=a^2-2ab+b^2 A=a^2-2ab+b^2-ab-b^2 A=a^2-3ab
[A/(a^2-b^2)]+[b/(a-b)]=(a-b)/(a+b), [A/(a+b)(a-b)]+[b/(a-b)]=(a-b)/(a+b), [A+b(a+b)]/(a+b)(a-b)=(a-b)/(a+b), [A+b(a+b)]=(a-b)^2 A=a(a-3b)
答:1、(a^2-2ab+b^2)/(a^2-b^20)=(a-b)^2/(a+b)(a-b)=(a-b)/(a+b) 2、【X/(X-3)】-2=(6-x)/(x...详情>>
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