Question

 

 

Tìm x 

8 mũ x = 2 mũ 111

2 mũ x + 5.2 mũ x = 48

2 mũ x + 3.2 mũ x-1 = 40

Answer 1

8^x=2¹¹¹

=>(2³)^x=2¹¹¹

=>2^3x=2¹¹¹

=>3x=111

=>x=37

2^x+5.2^x=48

=>2^x.6=48

=>2^x=8=2³

=>x=3

Câu cuối ko làm đc nha

Answer 2

a. 8^x = 2¹¹¹

    2^3x = 2¹¹¹

    3x  = 111

      x  = 111:3

     x  = 37

b. 2^x + 5.2^x = 48

    2^x(5 + 1 )= 48

    2^x.6        = 48

    2^x           = 48 : 6

    2^x           = 8

    2^x            = 2³

      x            = 3

c. 2^x + 3.2^x-1 = 40

   2^x(3:2 +1 )     = 40

   2^x . \(\frac{5}{2}\)      = 40

    2^x                  = 40 : \(\frac{5}{2}\)

    2^x                  = 16

    2^x                   = 2⁴

      x                   = 4

Answer 3

+) \(8^x=2^{111}\)

\(\Rightarrow\left(2^3\right)^x=2^{111}\)

\(\Rightarrow2^{3x}=2^{111}\)

\(\Rightarrow3x=111\)

\(\Rightarrow x=111:3\)

\(\Rightarrow x=37\)

Vậy x = 37

+) \(2^x+5\times2^x=48\)

\(\Rightarrow2^x\times\left(1+5\right)=48\)

\(\Rightarrow2^x\times6=48\)

\(\Rightarrow2^x=48:6\)

\(\Rightarrow2^x=8\)

\(\Rightarrow2^x=2^3\)

\(\Rightarrow x=3\)

Vậy x = 3

+) \(2^x+3\times2^{x-1}=40\)

\(\Rightarrow2^x+3\times2^x:2=40\)

\(\Rightarrow2^x+3\times2^x\times\frac{1}{2}=40\)

\(\Rightarrow2^x+2^x\times\left(3\times\frac{1}{2}\right)=40\)

\(\Rightarrow2^x+2^x\times\frac{3}{2}=40\)

\(\Rightarrow2^x\times\left(1+\frac{3}{2}\right)=40\)

\(\Rightarrow2^x\times\frac{5}{2}=40\)

\(\Rightarrow2^x=40:\frac{5}{2}\)

\(\Rightarrow2^x=16\)

\(\Rightarrow2^x=2^4\)

\(\Rightarrow x=4\)

Vậy x = 4

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