Akar-akar persamaan 2^x + 2^3-x = 9 adalah a dan b. Nilai a + b = A. 3 B. 4 C. 6 D. 8 E. 9

jangan lupa ya a nya 2^x

Mapel Matematika
Bab Eksponen

2^x + 2^(3 - x) = 9
2^x + (2^3)(2^-x) = 9
2^x + 8/2^x = 9
2^2x + 8 = 9(2^x)
2^2x - 9(2^x) + 8 = 0

Anggap
2^x = y
Maka

y^2 - 9y + 8 = 0
(y - 1)(y - 8) = 0
y = 1
y = 8

2^x = 1
2^x = 2^0
x = 0

2^x = 8
2^x = 2^3
x = 3

a + b = 0 + 3 = 3 (A)