cara penyelesaian? #mohon bantuannya

Bab Eksponensial
Matematika SMP Kelas IX

a] (1/4)^(x - 1) = 2^((3x + 1)/3)
     2^(-2(x - 1)) = 2((3x + 1)/3)
     -2x + 2 = (3x + 1)/3
    3 (-2x + 2) = 3x + 1
    -6x + 6 = 3x + 1
    -6x - 3x = 1 - 6
    -9x = -5 
    x = -5/-9
    x = 5/9

b] 5^((x + 2)/2) = 5²
    (x + 2)/2 = 2
    x + 2 = 2 . 2
    x = 4 - 2
    x = 2