Question

D and E are points on sides AB and AC respectively of triangle ABC such that DE || BC. If AD = x-1, DB = x – 3, AE = x + 3 and EC = x , the value of x is: ​

Answer 1

9514 1404 393

Answer:

9

Explanation:

The triangles are similar, so corresponding sides are proportional.

AE/AD = EC/DB

(x+3)/(x -1) = x/(x -3)

x^2 -9 = x^2 -x . . . . . . . cross multiply

x = 9 . . . . . . . . . . . add x+9-x^2 to both sides