Question 1034934
{{{drawing(800/3,400,-.5,1.5,-.5,2.5,

triangle(0,0,1,0,0,2.050303842),locate(0,0,A), locate(1,0,B),
locate(0,2.2,E), rectangle(.1,0,0,.1),
locate(.6,.15,2x+46),red(arc(1,0,.9,-.9,116,180)),
locate(.01,1.53,3x-1), red(arc(0,2.050303842,1.4,-1.4,270,296))

  )}}}

Since this is a right triangle, the sum of the
measures of the two acute angles is 90°.

  m∠B + m∠E = 90°
2x+46 + 3x-1 = 90
       5x+45 = 90
          5x = 45
           x = 9

m∠B = 2x+46 = 2(9)+46 = 18+46 = 64°

Edwin</pre>