Answer: x = 4
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Step-by-step explanation:
Have a look at the image I've attached below. I've basically marked up the three angles that we're focusing on. Angle LMW is in red while angle WMN is in green for the middle diagram. They combine or glue together to form angle LMN which is the light blue angle in the diagram on the right hand side. I made two diagrams to avoid any confusing overlapping colors.
So,
(angle LMW) + (angle WMN) = (angle LWN)
(13x-4) + (30x) = (168)
13x-4 + 30x = 168
(13x+30x) - 4 = 168
43x - 4 = 168
43x - 4+4 = 168+4 ....... adding 4 to both sides
43x = 172
43x/43 = 172/43 ........ dividing both sides by 43
x = 4 which is the answer