What is the value of x in the figure?

x = 100

Step-by-step explanation:

x + 23 + 57 = 180     {linear pair}

    x +  80   = 180

              x = 180 -80

             x = 100

100

Step-by-step explanation:

Since the line is straight you know that both angles add up to 180 degrees.

You can create this equation:

57+x+23=180

And then solve

80+x=180

x=100

Hope this helps!