Answer:
x=1
Step-by-step explanation:
Since the two triangles are similar you want to look at what two dimensions have x included and if they are similar. Both have the same angles and on the bottom they both have x.
In order to figure out the value you need to compare them:
3x + 1 = 4x
1 = 4x-3x
1 = x
x = 1
