Respuesta :

DeanR

That's Intersecting Secants, and we get


EC × ED = EB × EA


(x+4)(x+4+1) = (x+1)(x+1+11)


(x+4)(x+5) = (x+1)(x+12)


x^2 + 9x + 20 = x^2 + 13x + 12


8 = 4 x


x = 2


Check: 3(14)=42 6(7)=42 good


Answer: 2