Answer:
x = 10
[tex] m\angle DCE=55\degree [/tex]
Step-by-step explanation:
Since, CE bisects angle DCF, therefore:
[tex] m\angle ECF= m\angle DCE[/tex]
[tex] 6x-5=4x + 15 [/tex]
[tex] 6x-4x=5 + 15 [/tex]
[tex] 2x=20 [/tex]
[tex] x=\frac{20}{2} [/tex]
[tex] x=10[/tex]
[tex] m\angle DCE=(4x+15)\degree [/tex]
[tex] m\angle DCE=(4\times 10+15)\degree [/tex]
[tex] m\angle DCE=(40+15)\degree [/tex]
[tex] m\angle DCE=55\degree [/tex]
