Answer:
[tex]\large\boxed{GCF(28,\ 42)=14}[/tex]
Step-by-step explanation:
[tex]\begin{array}{c|c}28&2\\14&2\\7&7\\1\end{array}\\\\28=\boxed2\cdot2\cdot\boxed7\\\\\begin{array}{c|c}42&2\\21&3\\7&7\\1\end{array}\\\\42=\boxed2\cdot3\cdot\boxed7\\\\GCF(28,\ 42)=\boxed2\cdot\boxed7=14[/tex]
