Answer:
19
Step-by-step explanation:
if the triangles are similar then EG/BC = FG/BD
51/(x+4) = 57/(2x-7) cross multiply expressions
102x - 357 = 57x + 228
102x - 57x = 228 + 357
45x = 585 divide both sides by 45
x = 13
BD = 2x -7 and 13×2 - 7 = 19
