Given:
[tex]\begin{gathered} \text{If 6x=30 then x=5} \\ \text{If x=5 then 2x=10} \end{gathered}[/tex]The law of syllogism states that,
[tex]\text{ If a=}b\text{ and b=c then a=c}[/tex]For the given data,
[tex]\begin{gathered} a\colon\text{ 6x=30} \\ b\colon x=5 \\ c\colon2x=10 \\ By\text{ the law of syllogism,} \\ 6x=30 \\ 3\cdot2x=3\cdot10 \\ \Rightarrow2x=10 \\ Therefore, \\ \text{If 6x=30 then 2x=10} \end{gathered}[/tex]