Question

Soal Try-Out SBMPTN oleh ITB + LBB NF mat saintek
no 9 dan 10 ... ?

Answer 1

Misal,

x' = (1 - x)/2
2x' = 1 - x
x = 1 - 2x'

g(f(x)) = 3x + 1
g(x) = 3(1 - 2x) + 1
g(x) = 3 - 6x + 1
g(x) = -6x + 4

y = -6x + 4
6x = 4 - y
x = (4 - y)/6
g⁻¹(x) = (4 - x)/6

==========

log(u₄) + log(u₅) - log(u₆) = log(3)
log(u₄.u₅/u₆) = log(3)
u₄.u₅/u₆ = 3
12u₄/u₆ = 3
u₄/u₆ = 3/12
u₄/u₆ = 1/4
(ar³)/(ar⁵) = 1/4
1/r² = 1/4
r = 2

ar⁴ = 12
16a = 12
a = 12/16
a = 3/4

u₄ = ar³
= (3/4)(2)³
= 3*2
= 6