6)
The expression 2(r+3) can be written using distributive property as,
[tex]\begin{gathered} 2(r+3)=2r+2\times3 \\ =2r+6 \end{gathered}[/tex](Distributive property, A(B+C)=AB+AC).
Therefore, 2(r+3)=2r+6.
7)
The expression 6(4s-1) can be written using distributive property as,
[tex]\begin{gathered} 6(4s-1)=6\times4s-6\times1 \\ =24s-6 \end{gathered}[/tex]Therefore, 6(4s-1)=24s-6.
8)
8t+2 can be written as,
[tex]\begin{gathered} 8t+2=2\times4t+2\times1 \\ =2(4t+1) \end{gathered}[/tex]Therefore, 8t+2=2(4t+1).