Short answer: x = 40
Remark
All you are concerned about is the bottom triangle. It is isosceles, so the two base angles are equal. You are 1 step away from finding x.
Step one
Find he vertex angle (the top angle) of the triangle
Let the vertex angle = V
V + 70 + 70 = 180 Add the two 70s together.
V + 140 = 180 Subtract 140 from both sides.
V = 180 - 140
V = 40
Step Two
Find x
Since V and x are vertically opposite (you have to assume that or this question is unsolvable) then V = x
x = 40 degrees
Answer
x = 40 degrees
