Step-by-step explanation:
Given expression,
[tex]\\ {\longrightarrow \qquad{ \sf{6(x + 7) + 3x}}}\\ \\ [/tex]
Using distributive property we get,
[tex] \\ {\longrightarrow \qquad{ \sf{6x + 42 + 3x}}}\\ \\ [/tex]
Adding like terms (6x and 3x) we get,
[tex]\\ {\longrightarrow \qquad{ \sf{9x + 42 }}}\\ \\ [/tex]
So, From the given options, Option C is equivalent to 6(x + 7) + 3x .
