5)
{0.6x≤9, | :0.6 { x≤15
{1/3 x ≥2 | * 3 <=> {x≥6
\\\\\\\\\\\\\\\\\
///////////////////
------*-------*------>x
6 15
x∈[6; 15]
6)
{9x>0, | :9 {x>0
{1/7 x≥ -1 | * 7 <=> {x≥-7
\\\\\\\\\\\\\\\\\\\\\
////////////////////////////////
-----*--------о----->x
-7 0
x∈(0; +∞)