Answer:
opposite angles are equal, and since, the figure is a rectangle, all its sides measure 90 degrees. Which means, in the side with 47, the angle will be 90 degrees if the other angle is mentioned.( 90-47=43), and we know that opposite angles are equal, and on a line that divides the angles, 43 is equal to 6x+19. so, 6x+19=43,
6x=43-19=24
x=24/6=4
in the same way, the angle 47 mentioned in the figure is equal to the angle beside 6x+19