Respuesta :

    we know that

The Intersecting secant theorem established 
EC*ED=EB*EA
so
(x+4)*(x+5)=(x+1)*(x+12)--------> x²+5x+4x+20=x²+12x+x+12
x²+5x+4x+20=x²+12x+x+12-------> 9x+20=13x+12-----> 4x=8-----> x=2

the answer is x=2