Question

[nguyenthanhluan]

các bạn gúp mk với nhé:

Answer 1

[Ga'l wes]

d ) \(\left(2x-1\right)^2=25\)

\(\left(2x-1\right)^2=5^2\)hoặc \(\left(-5\right)^2\)

\(\Rightarrow\orbr{\begin{cases}2x-1=5\\2x-1=-5\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}2x=6\\2x=-4\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=3\\x=-2\end{cases}}\)

h ) \(2^{x-1}=16\)

\(2^{x-1}=2^4\)

\(\Rightarrow\)\(x-1=4\)

\(\Rightarrow\)\(x=5\)

Answer 2

[Ga'l wes]

i ) \(\left(\frac{4}{7}-\frac{1}{2}x\right)^3=8\)

\(\left(\frac{4}{7}-\frac{1}{2}x\right)^3=2^3\)

\(\Rightarrow\)\(\frac{4}{7}-\frac{1}{2}x=2\)

\(\Rightarrow\)\(\frac{1}{2}x=\frac{4}{7}-2\)

\(\Rightarrow\)\(\frac{1}{2}x=-\frac{10}{7}\)

\(\Rightarrow\)\(x=-\frac{20}{7}\)

k ) \(\left(x-\frac{1}{2}\right)^3=\frac{1}{27}\)

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

\(\Rightarrow\)\(x-\frac{1}{2}=\frac{1}{3}\)

\(\Rightarrow\)\(x=\frac{1}{3}+\frac{1}{2}=\frac{5}{6}\)