5x² ≤ 16x - 3;
5x² - 16x + 3 ≤ 0;
5x² - 16x + 3 = 0; D = 256 - 60 = 196; √D = 14;
x₁ = (16 + 14)/10 = 3; x₂ = (16 - 14)/10 = 0,2
+++++++ ------------------- ++++++++++++++++
-----------------0,2------------------------3------------------------------------->
x∈[0,2; 3].
Ответ: [0,2; 3].