plus Bantu ya, bentar lagi sb, tapi matdas nya Susah banget

6) alogb - bloga = -3
(alogb - bloga)^2 = (-3)^2
(alogb)^2 - 2 . alogb . bloga + (bloga)^2 = 9
(alogb)^2 - 2 . 1 + (bloga)^2 = 9
(alogb)^2 + (bloga)^2 = 9 + 2 = 11

7) sifat invers : f(x) = y => f^-1(y) = x
f^-1(a + 1) = 2 => f(2) = (a + 1)

f(1/(x + 1)) = (x + 3)/(x + 1)
1/(x + 1) = 2 => 2x + 2 = 1 => 2x = -1 => x = -1/2
f(1/(-1/2 + 1)) = (-1/2 + 3)/(-1/2 + 1)
f(1/(1/2)) = (5/2)/(1/2)
f(2) = 5

f(2) = a + 1 = 5 => a = 4

Jadi a - 3 = 4 - 3 = 1