tlg jawab beserta caranya

8.
10/(3 + √7)
= 10/(3 + √7) × (3 - √7)/(3 - √7)
= 10(3 - √7)/(9 - 7)
= 10(3 - √7)/2
= 5(3 - √7)

9.
U1 = a = 4
U2 = a + b = 7
U3 = a + 2b = 10
maka, b = 3
U10 = 4 + 9(3)
= 4 + 27
= 31