tolong dijawab yyy no 20,21,22

20) f(x) = 3x² + 2
f(-3) = 3(-3)² + 2
= 3(9) + 2
= 27 + 2
= 29 ( C )

21) f(x) = x³ + 1
f(1) = 1³ + 1 = 2
f(2) = 2³ + 1 = 9
f(3) = 3³ + 1 = 28
f(4) = 4³ + 1 = 65
hp = { ( 1,2) ( 2,9 )( 3,28)( 4,65)} ( C )

22) f(x) = 5x - 3
f(a) = 5a - 3
17 = 5a - 3
17 + 3 = 5a
20 = 5a
a = 4 (D)