Question

\(x^3:2=4\)

\(5^{x-2}=1\)

\(3^x+3^{x+1}+3^{x+2}=243.39\)

Answer 1

+) x³ : 2 = 4

x³ = 4 . 2 = 8

x³ = 2³

=> x = 2

+) 5^x-2 = 1

=> 5^x : 5² = 1

=> 5^x = 5²

=> x = 2

+) 3^x + 3^x+1 + 3^x+2 = 243 . 39

3^x + 3^x . 3 + 3^x . 3² = 9477

3^x . (1+3+ 3²) = 9477

3^x . 13 = 9477

3^x = \(\frac{9477}{13}\) = 729

3^x = 3⁶

=> x = 6

Answer 2

x³:2=4

\(\Rightarrow\)x³=4.2

\(\Rightarrow\)x³=8

\(\Rightarrow\)x³=2³

^{\(\Rightarrow\)}x=2

Vậy:x=2

5^x-2=1

\(\Rightarrow\)5^x-2=5⁰

\(\Rightarrow\)x-2=0

\(\Rightarrow\)x=2

Vậy:x=2

3^x+3^x+1+3^x+2=243.39

\(\Rightarrow\)3^x+3^x+1+3^x+2=9477

\(\Rightarrow\)3^x+3^x.3+3^x.3²=9477

\(\Rightarrow\)3^x=9477:13

\(\Rightarrow\)3^x=729

\(\Rightarrow\)3^x=3⁶

^{\(\Rightarrow\)}x=6

Vậy:x=6

Answer 3

+) \(x^3\):2=4

\(\Rightarrow\)\(x^3\)=4.2

\(\Rightarrow\)\(x^3\)=8

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

\(\Rightarrow\)\(x\) = 2

Vậy x=2

+) \(5^{x-2}\)=1

\(\Rightarrow\) \(5^{x-2}\)=\(5^0\)

\(\Rightarrow x-2=0\)

\(\Rightarrow x=0+2\)

\(\Rightarrow x=2\)

Vậy x=2

+) \(3^x+3^{x+1}+3^{x+2}=143.39\)

\(\Rightarrow\)\(3^x+3^{x+1}+3^{x+2}=9477\)

\(\Rightarrow\)\(3^x+3^x.3+3^x.9=9477\)

\(\Rightarrow3^x=9477:13\)

\(\Rightarrow3^x=729\)

\(\Rightarrow3^x=3^6\)

\(\Rightarrow x=6\)

Vậy x=6