Answer:
x = 100°
Step-by-step explanation:
The measure of a chord- chord angle is half the sum of the arcs intercepted by the angle and its vertical angle, that is
x =
(71 + 129)° = 0.5 × 200° = 100°
Expand
simplify 36 - 4.5x + 36 to -4.5x + 72
simplify 102 - 7.5x - 60 to -7.5x + 42
add 7.5x to both sides
simplify -4.5x + 72 + 7.5x to 3x + 72
subtract 72 from both sides
simplify 42 - 72 to -30
divide both sides by 3
simplify 30/3 to 10
Answer: x = -10