(x+8)(x-1)-x(x+5)=x²+8x-x-8-x²-5x=2x-8, 2x-8≤7, 2x≤15
(x+1)/6-x≤6 | *6, x+1-6x≤36, -5x≤35
{2x≤15 |:2 {x≤7,5
-5x≤35|:(-5) x≥-7
\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \
-------------|----------------|----------- > x
-7 7,5
/ / / / / / / / / / / / / / / / / /
x∈[-7;7,5]