"اَلْتِّلْفاز مُعَطَّل وَهٰذِهِ مُشْكِلة كَبيرة."
Translation:The television is out of order and this is a big problem.
An adjective can be used attributive (the big problem) and predicative (the problem is big). In Arabic, attributive use needs a match in definite article while predicative use has a mismatch in the definite article:
A big problem: مشكلة كبيرة and the big problem المشكلة الكبيرة vs. the problem is big المشكلة كبيرة.
Hope this helps understanding it a bit better.