Answer:
step 1. DBE ~ ABC
step 2. (x + 5)/4 = (2x + x + 5)/(4 + 3)
step 3. ( x + 5)/4 = (3x + 5)/7
step 4. 7x + 35 = 12x + 20
step 5. 5x = 15
step 6. x = 3.
