Respuesta :

Answer:

<4= 164

Step-by-step explanation:

the sum of any 2 angles of a triangle is equal to the exterior linear angle of the triangle

<1+<2=<4

8x+9+5x+12=14x+10

13x+21=14x+10

21=x+10

11=x

<4=14x+10

<4=14(11)+10

<4=154+10

<4= 164