help me is my third time posting this can anyone please help me 2 questions can at least answer 1 please

Answer:
For 11, x=18
Step-by-step explanation:
Use a ratio to solve for x since the triangles are similar
16/20=(16+12)/(20+x-3), first simplify both sides
4/5=28/(17+x), cross multiply
4(17+x)=5*28
17+x=5*7
x=35-16
x=18