Respuesta :

A straight line equals 180 degrees.

The two equations when added together make a straight line so needs to equal 180:

10x-20 + 6x +8 = 180

Simplify:

16x - 12 = 180

Add 12 to each side:

16x = 192

Divide both sides by 16:

X = 192 / 16

X = 12