Answer:
4
Step-by-step explanation:
You need to find XYW
<xYW = <XYZ - <WYZ
<XYW = 128 - 85
<XYW = 43
12x - 5 = 43 Add 5 to both sides
12x = 43 + 5
12x = 48 Divide by 12
x = 48/12
x = 4