Given that D is the mid point of CE ,
So D will bisect CE, it means the length of DE and CD is equal.
=> DE + CD = CE
As DE and CD are equal,
=> DE + DE = CE
=> 2 DE = CE
Putting values from the question,
=> 2( 7x - 1 ) = 10x + 18
=> 14x - 2 = 10x + 18
=> 14x - 10x = 18 + 2
=> 4x = 20
=> x = 20 / 4
=> x = 10 / 2
=> x = 5
Therefore, the value of x is 5
So D will bisect CE, it means the length of DE and CD is equal.
=> DE + CD = CE
As DE and CD are equal,
=> DE + DE = CE
=> 2 DE = CE
Putting values from the question,
=> 2( 7x - 1 ) = 10x + 18
=> 14x - 2 = 10x + 18
=> 14x - 10x = 18 + 2
=> 4x = 20
=> x = 20 / 4
=> x = 10 / 2
=> x = 5
Therefore, the value of x is 5