Answer
The average approval rating of Iran, China, and the UK is $-6$.
Work Step by Step
China's approval rating = $-10$
Iran's approval rating = $-29$
UK's approval rating = $21$
Thus, the average rating of the three countries is:
$=\dfrac{-10+(-29)+21}{3}
\\=\dfrac{-18}{3}
\\=-6$
The average approval rating of Iran, China, and the UK is $-6$.
