a straight line is 180 degrees so we can find C by subtracting 140 from 180
180-140 = 40 degrees
all 3 inside angles need to equal 180 so now we have
180 = 40 + (2x) + (x+2)
180 = 40 +3x +2
180=42+3x
138=3x
x= 138/3 = 46
check : 2x= 2*46 = 92
x+2 = 46+2 = 48
92 +48 +40 = 180
so x = 46 degrees
so angle B = 2x46 = 92 degrees