Question

what is the value of x?

Answer 1

since the length of two sides are equal then the angles opposite these sides will also be equal
ie. this is an isosceles triangle
therefore, 
              x = (180 - 38)/2
                 = 142 / 2
                 = 71

Answer 2

this is an isosceles triangle so the angle opposite to the equal sides are equal . after this using angle sum property
x+x+38=180
2x=180-38
x=142÷2
x=71