Find angle b if triangle abc below is isosceles.

a: 77 degrees
b: 36 degrees
c: 50 degrees
d: 44 degrees

So these will equal each other so put them to equal to find x
2x-20=x+8
   +20     +20
2x=x+28
 -x    -x
x=28 now plug it in 
2(28)-20= 36
(28)+8= 36, since they're equal this make it an isosolece and it's correct 
So the answer is B. hope this helped you have a great day!!

Use the Isosceles Triangle Theorems. The Base Angles Theorem. If two sides of a triangle are congruent, then the angles opposite those sides are congruent. Converse of the Base Angles Theorem. So, X + 8 = 2X - 20
                         subtract x from both sides    -X         -X
                           new equation                           8 = X - 20
                     add 20 to both sides                    +20     +20
                                                                         28 = X
Angle B =    X + 8        
sub 28 for X   (28 + 8 =  36)

What’s the equation you are trying to solve to get x?