If Forces are acting on opposite direction
[tex]\\ \rm\hookrightarrow F_{net}=F_2-F_1[/tex]
[tex]\\ \rm\hookrightarrow F_{net}=10-6[/tex]
[tex]\\ \rm\hookrightarrow F_{net}=4N[/tex]
If both acting on same direction
[tex]\\ \rm\hookrightarrow F_{net}=F_1+F_2[/tex]
[tex]\\ \rm\hookrightarrow F_{net}=10+6[/tex]
[tex]\\ \rm\hookrightarrow F_{net}=16N[/tex]
Hence
[tex]\boxed{\sf 4N\leqslant F_{net}\leqslant 16N}[/tex]