<PRE><B>Question 31022</B>
I am not sure how to draw this problem on this site but angle BED will equal and CEA because they are opposite angles.  A form of a rule from Geometry.  First we need to find these angles

{{{5x+20=7x+10}}} subtract 10 from both sides
{{{5x+10=7x}}} subtract 5x from both sides
{{{10=2x}}} divide by 2
{{{5=x}}}  
These angles equal 5 degrees.  Knowing that the angle of a line is 180 degrees.

{{{180-5=x}}}
{{{175=x}}}

CEB = 175 degrees</PRE>