Answer:
7
Explanation:
Took me a long time to figure this one out (I was using trigonometry, angles, and so much more and just realized that it's actually pretty simple, lol)
So this has to do with ratios. The ratio of one side to the other for each triangle, is the same for the 2 triangles. So the ratio of 12 to 9 is the same as 16 to (2x-2), so we can write it as a fraction:
12/9=16/(2x-2)
12(2x-2)=16(9) (I cross multiplied)
24x-24=144 (distribution)
24x=168 (adding 24 to both sides)
x=7 (divided both sides by 24)
Hope that this helps!