a. (7x+2)^2=13^2

7x+2=13

7x=11

x=11/7

b.(4x-2)^3=5^3

4x-2=5

4x=7

x=7/4

c.(2x)^4=3^4

2x=3

x=3/2

a,(7x+2)²=169

(7x+2)²=13²

^7x+2=13

^7x=13-2

^7x=11

^x=11/7

b(4x-2)³=125

(4x-2)³=5³

4x-2=5

4x=5+2

4x=7

x=7/4

c(x+x)⁴=81

(x+x)⁴=3⁴

x+x=3

2x=3

x=3:2

x=1,5

a. \(\left(7x+2\right)^2=169\) \(\Rightarrow\left(7x+2\right)^2=13^2\Rightarrow7x+2=13\Rightarrow7x=11\Rightarrow x=\frac{11}{7}\)

b . \(\left(4x-2\right)^3=125\Rightarrow\left(4x-2\right)^3=5^3\Rightarrow4x-2=5\Rightarrow4x=7\Rightarrow x=\frac{7}{4}\)

c. \(\left(x+x\right)^4=81\Rightarrow\left(x+x\right)^4=3^4\Rightarrow x+x=3\Rightarrow2x=3\Rightarrow x=\frac{3}{2}\)

a) (7x+2)² = 169

<=> 7x+2 = 13

7x = 13 - 2

7x = 11

x = 11:7

\(x=\frac{11}{7}\)

b) (4x-2)³ = 125

<=> 4x-2 = 5

4x = 5+2

4x = 7

x = 7:4

\(x=\frac{7}{4}\)

c) (x+x)⁴ = 81

<=> 2x = 3

x = 3:2

\(x=\frac{3}{2}\)

a, \(\left(7x+2\right)^2=169\)

\(\Leftrightarrow\orbr{\begin{cases}\left(7x+2\right)^2=13^2\\\left(7x+2\right)^2=\left(-13\right)^2\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}7x+2=13\\7x+2=-13\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}7x=13-2\\7x=-13-2\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}7x=11\\7x=-15\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{11}{7}\\x=\frac{-15}{7}\end{cases}}\)

b, \(\left(4x-2\right)^3=125\)

\(\Leftrightarrow\left(4x-2\right)^3=5^3\)

\(\Leftrightarrow4x-2=5\)

\(\Leftrightarrow4x=5+2=7\)

\(\Leftrightarrow x=\frac{7}{4}\)

c,\(\left(x+x\right)^4=81\)

\(\Leftrightarrow\orbr{\begin{cases}\left(2x\right)^4=3^4\\\left(2x\right)^4=\left(-3\right)^4\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}2x=3\\2x=-3\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{-3}{2}\end{cases}}\)

\(a,\left(7x+2\right)^2=169\)
\(\left(7x+2\right)^2=13^2\)          
\(7x+2=13\)        \(7x+2=-13\)

\(x=\frac{11}{7}\)                   còn 1 TH nữa
\(b,\left(4x-2\right)^3=125\)
\(4x-2=5\)
\(x=\frac{7}{4}\)