zanykmarkooyjp1p Log0.8(x)+log0.8(x+1)≤log0.8(8-x)
x ∈ (0,8)
log0.8(x×(x+1))≤log0.8(8-x)
log0.8(x²+x)≤log0.8(8-x)
x²+x≥8-x
x²+x-8+x≥0
x²+4x-2x-8≥0
x×(x+4)-2(x+4)≥0
(x-2)×(x+4)≥0
                 
система { x-2≥0;        система {  x≥2
                 x+4≥0;                         x≥ -4

система { x-2≤0;        система {  x≤2
                 x+4≤0;                         x≤ -4
 x ∈ [2;+∞ ]
 x ∈ (-∞;-4)
 x ∈ (-∞;-4] ∪ [2;+∞), x ∈ (0;8)

Ответ: x ∈ [2;8).