GCF = Greatest Common Factor
Therefore,
prime factor of 42
[tex]42\text{ = }2\times3\times7[/tex]
prime factor of 36
[tex]36=2\times2\times3\times3[/tex][tex]As\text{ 2}\times3=6,\text{ GCF=6}[/tex]
Therefore,
[tex]42+36=6\times7+6\times6=6\times(7+6)[/tex]
