100Points! show work

Using angle sum property
[tex]\\ \sf\longmapsto x+43+73+70=180[/tex]
[tex]\\ \sf\longmapsto x+43+143=180[/tex]
[tex]\\ \sf\longmapsto x+186=180[/tex]
[tex]\\ \sf\longmapsto x=180-186[/tex]
[tex]\\ \sf\longmapsto x=-6[/tex]
Option C is correct
Sum of angles of any triangle is 180°
Option C