Respuesta :

Answer: x=8

Step-by-step explanation:

15*8 = 120 + 20 = 140

140+40 = 180 a perfect line

Answer:

Below

Step-by-step explanation:

Angle on a straight line =180

[tex]40\° + (15x +20)\°=180\°\\\\40 \°+(15(8)+20)\° =180\°\\\\40\°+(120+20)\°=180\°\\\\40\°+140\°=180\°\\\\180\°=180\°[/tex]