Answer:
x = 7
Step-by-step explanation:
You need to figure which sides correspond and set up the proportions
Labeling the vertices of the triangles would help you.
I did that and found that 5x - 15 ↔ 10 since both of those sides are opposite the 42° angles and 36 ↔ 18
So [tex]\frac{5x - 15}{10} = \frac{36}{18\\}[/tex]
18(5x - 15) = 10(36)
90x - 270 = 360
90x = 630
x = 7
