ОДЗ
x > 3
log2 (x) + log2 (x - 3) > log2 (4)
log2 (x (x - 3) ) > log2 (4)
Так как 2 > 1, знак не меняем
x (x - 3) > 4
x (x - 3) - 4 > 0
x^2 - 3x - 4 > 0
x^2 - 3x - 4 = 0
D = 9 + 16 = 25
x1 = ( 3 + 5)/2 = 4
x2 = (3 - 5)/2 = - 1
+ ОДЗ
(x + 1)(x - 4) > 0
+ - +
********** ( - 1) -------(3)--------(4)*************> x
************************
x > 4
x ∈ ( 4 ; + ∞)