What expression represents the measure of angle x?

An isosceles triangle is a triangle that has 2 equal sides and 2 equal angles. 

side XY = side XZ
∠Y = ∠Z
Since ∠Y = a°  then ∠Z = a°

Because interior angles of a triangle sum up to 180°, we simply need to find the difference between 180° and the 2 known angles to solve for the measure of angle X.

∠X = 180° - 2a°
  

The correct graph is the second one, with the points being at (-6,0), (2,0) and reaching down to (-2,-8)

Ifound this on google “that means that the graph of a function with direct variation has these features: it is a straight line: because the slope is the ratio y/x = k. it passes through the origin (0,0): because y = kx = k (0) = 0.” i hope this you for what your looking for