1.设3^a=4^b=36,则2/a+1/b=?

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1.设3^a=4^b=36,则2/a+1/b=?
2.已知log8^9=a,log2^5=b,则lg3=?
3.若lga、lgb是方程2x^2-4x+1=0的两个实数根,求lg（ab）（lga/b）^2的值

3^a=4^b=36
==>a=log3 36=log3 4+log3 9=2log3 2+2
==>b=log4 36=log4 4+log4 9=1+log2 3
==>2/a+1/b=1/(1+log3 2)+1/(1+log2 3)=lg3/(lg2+lg3)+lg2/(lg2+lg3)=1

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