We have to put values of domain to find range
[tex]\\ \ast\sf\longmapsto y=3x+1[/tex]
[tex]\\ \ast\sf\longmapsto D_R=[-1,0,1][/tex]
[tex]\\ \ast\sf\longmapsto y=3(-1)+1=-3+1=-2[/tex]
[tex]\\ \ast\sf\longmapsto y=3(0)+1=0+1=1[/tex]
[tex]\\ \ast\sf\longmapsto y=3(4)+1=12+1=13[/tex]
Now
[tex]\\ \ast\sf\longmapsto R_R=[-2,1,13][/tex]
