Respuesta :

Answer:

x = 17.5 mm

Step-by-step explanation:

Supplementary means that two angles adds up to 180 degrees.

If C and D are supplementary, that means that they equal to 180 degrees.

Combine like terms:  6x - 4 + 4 + 4x + 9 - 9 = 180 + 4 - 9

10x / 10 = 175 / 10

x = 17.5

So, x = 17.5 mm

RELAXING NOICE
Relax