Answer:
x=6
Step-by-step explanation:
The two triangles shown are similar (AAA: they share the angle on the right and the two other angles are corresponding and therefore equal).
Since, they're similar, the sides are in ratio to eachother:
[tex]\frac{x+(x+3)}{8+12} = \frac{x+3}{12}[/tex]
12(2x+3)=20(x+3)
24x+36=20x+60
4x=24
x=6
