When will the resultant of the two vectors be at a maximum?

F=3n+1n=4n F=f1+f2={-4n)+(12n)=8n right (2) F=f1+f2=-4+2=-2n (3)F=f1+f2={6n)up+(-10n)down=-4n resultant to horizontal is 8n the right (2) resultant to vertical is -4n to the down