Respuesta :

Medunno13

Answer: 18

Step-by-step explanation:

By the exterior angle theorem,

[tex]x+18+x+12=x+48\\\\2x+30=x+48\\\\x+30=48\\\\x=18[/tex]

KurdishPotato

Answer:

x = 18

Step-by-step explanation:

The sum of two interior angles im a triangle is equal to one exterior angle that is supplementary to the third interior angle:

x + 18 + x + 12 = x + 48 add like terms

2x + 30 = x + 48 transfer like terms to the same side of the equation

2x - x = 48 - 30

x = 18