Hasil dari 3 pangkat x + 3 pangkat 3-X -28

3^x + 3^(3-x) -28 = 0
3^x + 3^3.1/3^x - 28 = 0
3^x + 27/3^x - 28 = 0. (kalikan 3^x )
(3^x)^2 +27 - 28.3^x = 0
(3^x)^2 - 28.3^x + 27 = 0
misal 3^x = a, maka
a^2 -28a + 27 = 0
(a - 1) (a -27) = 0
a = 1 atau a = 27
untuk a = 1. ==» 3^x = 1
3^x = 3^0
x = 0
untuk a = 27. ==» 3^x = 27
3^x = 3^3
x = 3
Jadi HP = { 0, 3 }