Answer:Step-by-step explanation:8) looking at the figure at number 8,It is a quadrilateral. In a quadrilateral, the opposite angles are supplementary. This means that the sum of all the angles is 360 degrees. We have assigned y degrees to the remaining unknown angle. y = 180 - 71 = 109 degrees( this is because the sum of angles on a straight line is 180 degrees. Therefore10x + 6 + 8x - 1 + 13x - 2 + 109 = 36031x + 112 = 36031x = 360 - 112 = 248x = 248/31 = 89) looking at the figure, we have assigned alphabets a, b and c to represent the inner angles that form the triangle.a + 9x + 1 = 180a = 180 - 1 -9x = 179 - 9x(this is because the sum of the angles on a straight line is 180 degrees)b + 5x + 12 = 180b = 180 - 12 - 5x b = 168 - 5x c + 10x -37 = 180c = 180 - 10x + 37 c = 217 - 10xa + b + c = 180( sum of angles in a triangle is 180 degrees)179 - 9x + 168 - 5x + 217 - 10x = 180-9x - 5x - 10x = 180 - 179 - 168 - 217-24x = -384x = -384/-24x = 16