Find the value of x in the figure

Answer:
x = 100
Step-by-step explanation:
180-57 would equal 123 which means 123 = x +23 and you can simplify this equation by moving 23 over to 123 and subtracting them leaving x = 100
123 = x+ 23
-23 + 123 = x
100 = x
x = 100
sorry, i'm really bad at explaining
180 degree angles when added
180-57 (for known angle)= 123
x+23=123<- we need to take off the all known angles to get x
123-123=100
x=100 is the answer