Find the bigger triangle first
You are already giver 70 and 35 degrees. A triangle is 180 total
70+35=180
-75
So the two tips of the triangles that are touching are equal
The knowledge you now have is 2x, x, and 75. You also know that the total has to be 180
2x+x+75=180
3x+75=180
-75 -75
3x=105
/3 /3
X=35