A)

(x-3)(x+4)≤0

{x-3≤0

{x+4≥0

{x-3≥0

{x+4≤0

{x≤3

{x≥-4

{x≥3

{x≤-4

x є [-4,3]

∅

Б)

[tex] \frac{5x - 2}{4} - \frac{3 - x}{5} > \frac{1 - x}{10} \\ 5(5x - 2) - 4(3 - x) > 2(1 - x) \\ 25x - 10 - 12 + 4x > 2 - 2x \\ 29x - 22 > 2 - 2x \\ 29x + 2x > 2 + 22 \\ 31x > 24 \\ x > \frac{24}{31} [/tex]