please jawabannya kakak- kakak

^ tanda pangkat
3^4-x + 3^x - 30 = 0
3^4/3^x + 3^x - 30 = 0
81/3^x + 3^x - 30 = 0
misalkan 3^x = p
81/p + p - 30 = 0
kalikan dengan p
81 + p² - 30p = 0
p² - 30p + 81 = 0
(p - 27)(p - 3) = 0
p = 27 atau p = 3
3^x = 27
3^x = 3³
x1 = 3
3^x = 3
3^x = 3¹
x2 = 1
x1³ + x2³ = 3³ + 1³ = 27 + 1 = 28