Answer:
FD = 8
Step-by-step explanation:
since they are similar triangle .use these ratios to find FD
AB/DE = AC/FD
now substitute the values
6/x-3 = 12/x+1
do cross multiplication
12(x-3) = 6(x+1)
12x - 36 = 6x + 6
12x - 6x = 6 + 36
6x = 42
x = 42/6
x = 7
now substitute x
FD = x + 1
=7 + 1
=8
