Question

tìm x

1) 2.3\(^x\) -5=7\(^2\) 

2) 3\(^{x+1}\) +1=27

3) 5\(^{x-2}\) =1

4) 9\(^{x-1}\) =1

Answer 1

1 ) 2.3^x - 5 = 7² <=> 2.3^x - 5 = 49 <=> 2.3^x = 54 => 3^x = 27 = 3³ => x = 3

2 ) 3^{x + 1} = 27 => 3^{x + 1} = 3³ => x + 1 = 3 => x = 2

3 ) 5^x-2 = 1 = 5⁰ => x - 2= 0 => x = 2

4 ) 9^x-1 = 1 = 9⁰ => x - 1 = 0 => x = 1

Answer 2

1)2.3^x-5=49=>2.3^x=54=>3^x=27=>x=3

2)3^x+1=26=>x+1=3=>x=2

3)5^x-2=1=>5^0=>x-2=0=>x=2

4)9^x-1=1=>9^0=x-1=0=>x=1

Answer 3

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