Answer: x=9.
Step-by-step explanation:
Triangle ABC is similar to triangle FED ⇒
[tex]\frac{77}{21} =\frac{11x+11}{30} \\\\\frac{7*11}{7*3}=\frac{11*(x+1)}{30} \\\\\frac{11}{3}*30 =11*(x+1)\\\\\frac{11*3*10}{3} =11*(x+1)\\\\11*10=11*(x+1)\\10=x+1\\9=x.[/tex]
Good luck an' have a nice day!
