5y-4>или равно 6
4-y< или равно 3
Это система

{5y-4≥6
{4-y≤3

{5y≥6+4
{-y≤3-4

{5y≥10
{-y≤-1

{y≥2
{y≥1
                               \\\\\\\\\\\\\\\\\\\\\\\\\
----------- 1 ----------- 2 -----------------
               \\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\
у≥2 или у∈[2; +∞)

Ответ [2; = ∞)