已知(2a-b)/(a+2b)=3/14,求(a²﹢b²)/(a²-b²)的值.问一道分式的题速度~~~急需~~~
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已知(2a-b)/(a+2b)=3/14,求(a²﹢b²)/(a²-b²)的值.问一道分式的题速度~~~急需~~~
已知(2a-b)/(a+2b)=3/14,求(a²﹢b²)/(a²-b²)的值.
问一道分式的题
速度~~~急需~~~
已知(2a-b)/(a+2b)=3/14,求(a²﹢b²)/(a²-b²)的值.问一道分式的题速度~~~急需~~~
(2a-b)/(a+2b)=3/14
3(a+2b)=14(2a-b)
3a+6b=28a-14b
28a-3a=6+14b
25a=20b
a=0.8b
(a²﹢b²)/(a²-b²)
=(0.64b²+b²)/(0.64b²-b²)
=1.64b²/-0.36b²
=-41/9
5a=4b
(a²﹢b²)/(a²-b²)=41/9
由已知条件(2a-b)/(a+2b)=3/14化简得
3(a+2b)=14(2a-b) => a=4b/5
所以(a²﹢b²)/(a²-b²)=(16b²+25b²)/(16b²-25b²)
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由已知条件(2a-b)/(a+2b)=3/14化简得
3(a+2b)=14(2a-b) => a=4b/5
所以(a²﹢b²)/(a²-b²)=(16b²+25b²)/(16b²-25b²)
=41/(-9)
=-41/9
即(a²﹢b²)/(a²-b²)=-41/9
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