Answer:
Q18: x = 21, y = 15
Q19: x = 16, y = 10
Q20: x = 24, y = 19
Explanation:
Q18:
(3x - 16) + (6x + 7) = 180 (corresponding angles, sum of angles on a straight line=180°)
9x - 9 = 180
9x = 189
x = 21
11y - 32 = 6x + 7 (vertically opposite angles)
11y - 32 = 6(21) + 7
11y - 32 = 133
11y = 165
y = 15
Q19:
8x - 14 = 5x + 34 (corresponding angles, vertically opposite angles)
3x = 48
x = 16
(8x - 14) + (5y + 16) = 180 (sum of angles on a straight line=180°)
8(16)-14 + (5y + 16) = 180
114 + 5y + 16 = 180
5y + 130 = 180
5y = 50
y = 10
Q20:
47 + 3x + (2x + 13) = 180 (corresponding angles, sum of angles on a straight line=180°)
5x + 60 = 180
5x = 120
x = 24
5y - 23 = 3x (corresponding angles)
5y - 23 = 3(24)
5y - 23 = 72
5y = 95
y = 19