<PRE><B>Question 1145852</B>
No.  Not angle m.
Angle B is 12x+6.


If the base is side AC, then the two base angles, congruent, are the interior angle at A and the interior angle at C.


If this is what you meant, then:
{{{(12x+6)+2(7x+22)=180}}}
-
{{{12x+6+14x+44=180}}}
{{{26x+50=180}}}
{{{26x=130}}}
{{{highlight_green(x=5)}}}



A, 57
B, 66
C, 57</PRE>