To factor the expression
[tex]42xy-7x+24my-4m[/tex]we notice that the first two terms have in common an x and a seven; the last two terms have in common an m and a 4. then we have:
[tex]42xy-7x+24my-4m=7x(6y-1)+4m(6y-1)[/tex]now we notice that the term (6y-1) appears in both terms, this means that this is now a common factor, then:
[tex]7x(6y-1)+4m(6y-1)=(6y-1)(7x+4m)[/tex]Therefore:
[tex]42xy-7x+24my-4m=(6y-1)(7x+4m)[/tex]