Question

Solve for CD using the following image

Answer 1

Answer:

$CD = CB - DB \\ CD = 12 - (x - 9) \\ { \tt{but \: CD = 2x - 9}} : \\ 2x - 9 = 21 - x \\ 3x = 30 \\ x = 10 \\ \\ { \bf{CD = 12 - (10 - 9)}} \\ CD = 11$

Answer 2

Here,

BC = 12

CD+BD=12

2x-9+x-9 =12

3x-18 12

3x =12+18

x =30/3

x =10

Now,

CD = 2x-9

= 2×10-9

= 20-9

= 11

Therefore,CD = 11

Hope this solution may help you!!☺