Here we use the property, angles opposite to equal sides are equal,
(5x+27)=(45+3x)
5x-3x=45-27
2x =18
x=18/2
x=9
Answer is D. x=9
[tex]m\angle DCA=m\angle BCA\ \text{therefore:}\\\\5x+27=45+3x\ \ \ |-27\\\\5x=18+3x\ \ \ \ |-3x\\\\2x=18\ \ \ \ |:2\\\\x=9[/tex]
Answer: 9