What is the formula for this? I need help with this really badly

Answer:
x=7
Step-by-step explanation:
We know that When we total the angles in the same arm od trapezoid wee will obtain 180°.
Hence :
12x+3+13x+2=180
25x+5=180
5x+1=36
5x=35
x=7
Greetings From Poland :)