To find the value of x you u have to add all angles
68 + x + (x - 24) = 180
Remove parenthesis
68 + x + x - 24 = 180
Combine like terms
44 + 2x = 180
Get x on one side of the equation
44 + 2x = 180
-44 -44
2x = 136
Divide each side by 2 to isolate x
2x/2 = 136/2
x = 68
now that you have x you can put it into the equations
A = 68°
B = (x - 24)
B = (68 - 24)
B = 44°