\[ \frac{515}{x+35} = 5 \]

\[ \Rightarrow 515 = 5(x + 35) \]

\[ \Rightarrow 515 = 5x + 175 \]

\[ \Rightarrow 5x = 515 - 175 \]

\[ \Rightarrow 5x = 340 \]

\[ \Rightarrow x = \frac{340}{5} \]

\[ \Rightarrow x = 68 \]

Vậy \(x = 68\).


\[ 20 - 2(x + 4) = 4 \]

\[ \Rightarrow 20 - 2x - 8 = 4 \]

\[ \Rightarrow 12 - 2x = 4 \]

\[ \Rightarrow -2x = 4 - 12 \]

\[ \Rightarrow -2x = -8 \]

\[ \Rightarrow x = \frac{-8}{-2} \]

\[ \Rightarrow x = 4 \]

Vậy \(x = 4\).


\[ (10 + 2x) \times 4^{2011} = 4^{2013} \]

\[ 10 + 2x = 4^{2013 - 2011} \]

\[ 10 + 2x = 4^2 \]

\[ 10 + 2x = 16 \]

\[ 2x = 16 - 10 \]

\[ 2x = 6 \]

\[ x = \frac{6}{2} \]

\[ x = 3 \]

Vậy \(x = 3\).

\[ 12 \times \frac{x - 1}{2} = 4^3 + 2^3 \]

\[ 6(x - 1) = 64 + 8 \]

\[ 6x - 6 = 72 \]

\[ 6x = 78 \]

\[ x = \frac{78}{6} \]

\[ x = 13 \]

Vậy \(x = 13\).