Question

b, x mũ 13= 27. x mũ 16

c, 1/2 mũ 2x-1 = 1/8 

giúp mình với mn ơi, để mình lm kịp trg chiều ni

 

Answer 1

x¹³ = 27.x¹⁶

=> x¹³ - 27x¹⁶ = 0

=> x¹³(1 - 27x³) = 0

=> \(\orbr{\begin{cases}x^{13}=0\\1-27x^3=0\end{cases}}\)

=> \(\orbr{\begin{cases}x=0\\27x^3=1\end{cases}}\)

=> \(\orbr{\begin{cases}x=0\\x^3=\frac{1}{27}\end{cases}}\)

=> \(\orbr{\begin{cases}x=0\\x=\frac{1}{3}\end{cases}}\)

c) \(\left(\frac{1}{2}\right)^{2x-1}=\frac{1}{8}\)

=> \(\left(\frac{1}{2}\right)^{2x-1}=\left(\frac{1}{2}\right)^3\)

=> \(2x-1=3\)

=> \(2x=3+1\)

=> \(2x=4\)

=> \(x=4:2=2\)

Answer 2

\(b,\text{ }x^{13}=27\cdot x^{16}\)

\(x^{16}\text{ : }x^{13}=27\)

\(x^3=3^3\)

\(x=3\)

Answer 3

\(b,\text{ }x^{13}=27\cdot x^{16}\)

\(x^{16}\text{ : }x^{13}=27\)

\(x^3=3^3\)

\(x=3\)

Answer 4

\(c,\text{ }\left(\frac{1}{2}\right)^{2x-1}=\frac{1}{8}\)

\(\left(\frac{1}{2}\right)^{2x-1}=\left(\frac{1}{2}\right)^3\)

\(2x-1=3\)

\(2x=3+1\)

\(2x=4\)

\(x=4\text{ : }2\)

\(x=2\)

Answer 5

\(c,\text{ }\left(\frac{1}{2}\right)^{2x-1}=\frac{1}{8}\)

\(\left(\frac{1}{2}\right)^{2x-1}=\left(\frac{1}{2}\right)^3\)

\(2x-1=3\)

\(2x=3+1\)

\(2x=4\)

\(x=4\text{ : }2\)

\(x=2\)

Answer 6

b)x¹³=27.x¹⁶

x¹⁶:x¹³=27

x³=3³

x=3

vậy x=3

c)(1/2)^2x-1=1/8

(1/2)^2x-1=(1/2)³

2x-1=3

2x=3+1

2x=4

  x=4:2

  x=2

vậy x=2