Quadratic Equation (Log)?

2016-10-08 1:56 pm
1) 3^2x - 7(3^x)-18 =0
2) 5^(2x+1) -24(5^x)-5 =0

回答 (1)

2016-10-09 2:20 am
1)
3^2x - 7(3^x)-18 =0
3^x=9 or 3^x=-2 (delete)
x=2
a^x>0 or a^x=0

2)
5^(2x+1) -24(5^x)-5 =0
(5)(5^2x)-24(5^x)-5=0
5^x=5 or 5^x=-0.2 (delete)
x=1


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