7.
1) Given (info from top)
2) <BCA =~ <DCE (vertical angles theorem)
3) triangle BCA =~ triangle DCE (SAS)
4) BA =~ ED (CPCTC)
=~ means congruent
8.
1) Given
2) CA =~ AC (reflexive property of equality)
3) triangle ACB =~ triangle ACD (ASA)
4) BC =~ CD (CPCTC)
Hope this helps!! :)