Jawabanmu

2014-09-08T14:09:20+07:00
 3^{x+2}  +  3^{2(x+1)} -810=0  --> 3^{2} .  3^{x} +  3^{2} .   (3^{x}) ^{2} -810



misal y=3^x maka  9y +9 y² -810=0

atau  y² +y-90=0  --> (y-9)(y+10)=0 maka y=9 ayau  3^{x} = 9 ... x=2

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