In triangle ABC, DE ∥ BC with D on AB and E on AC. If AD = x cm, DB = (x − 2) cm, AE = (x + 2) cm and EC = (x − 1) cm, find x.

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4. By the basic proportionality theorem, x/x - 2 = x + 2/x - 1. Cross-multiplying: x^2 - x = x^2 - 4, so x = 4. (Check: 4 : 2 = 6 : 3.)

In triangle ABC, DE ∥ BC with D on AB and E on AC. If AD = $x$ cm, DB = $(x - 2)$ cm, AE = $(x + 2)$ cm and EC = $(x - 1)$ cm, find $x$ .