[tex]\begin{gathered} w=\text{ number of cows} \\ c=\text{ number of chickens} \\ \text{There were 60 cows and chickens} \\ \text{Hence} \\ w+c=60 \\ \text{Now,} \\ \text{cows have 4 legs, and chickens have 2 legs, so} \\ 4w+2c=156 \\ \text{The system equation is } \\ w+c=60 \\ 4w+2c=156 \end{gathered}[/tex]
