Explanation:
what equals 8 ?????
what do you mean by that ? there is no 8 in the graph.
I can answer the question in the picture :
there are 2 parallel lines (l and m) intersected by 2 other lines with corresponding intersection angles.
the easiest to see is the intersection angle of 33°, as it involves only one intersecting line.
per rules of intersecting lines, the angles on both sides of the intersected line are equal, just left-right mirrored.
and the angles with parallel lines must be equal, as parallel lines imitate exactly each other's behavior.
that means the angle left of the 80° angle must be 33° too.
and now, the sum of all angles around a single point on one side of a line must be 180°, because that simulates a half-circle (a full circle = 360°, a half-circle = 180°).
so,
180 = 33 + 80 + x
67° = x