Question

a)2^x.4=128

b)x¹⁵=x

c)(2x+1)³=125

d)(x-5)⁴=(x-5)⁶

Answer 1

a) \(2^x.4=128\)

\(\Rightarrow2^x=128:4=32\)

Mà \(32=2^5\)

\(\Rightarrow2^x=2^5\)

Vậy x = 5

b) \(x^{15}=x\)

\(\Rightarrow x=\left\{0;1;-1\right\}\)

c) Ta có: \(125=5^3\)

\(\Rightarrow2x+1=5\)

\(\Rightarrow2x=5-1=4\)

\(\Rightarrow x=4:2=2\)

Vậy x = 2

d) Ta có: \(\left(x-5\right)^4=\left(x-5\right)^6\)

\(\Rightarrow x=5\)

Ủng hộ tớ nha?

Answer 2

\(2^x.4=128\)

\(\Rightarrow2^x.2^2=2^7\)

\(\Rightarrow x+2=7\)

\(\Rightarrow x=5\)

\(x^{15}=x\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=+-1\end{cases}}\)

\(\left(2x+1\right)^3=125\)

\(\Rightarrow2x+1=5\)

\(\Rightarrow2x=4\)

\(\Rightarrow x=2\)

Answer 3

a) 2x.4=128

⇒2x=128:4=32

Mà 32=25

⇒2x=25

Vậy x = 5

b) x15=x

⇒x={0;1;−1}

c) Ta có: 125=53

⇒2x+1=5

⇒2x=5−1=4

⇒x=4:2=2

Vậy x = 2

d) Ta có: (x−5)4=(x−5)6

⇒x=5