решительно неравенство -15/(x+1)²-3≥0

-15-3(x+1)^2≥(x+1)^2
-15-3(x^2+2x+1)≥x^2+2x+1
-15-3x^2-6x-3≥x^2+2x+1
-15-3x^2-6x-3-x^2-2x-1≥0
-4x^2-8x-19≥0
x(-4x-8)-19≥0
x≥0
-4x-8-19≥0
-4x-27≥0
-4x≥27
x≤-6.75

_____________0////////>
\\\\\\\\-6.75_____>

x∉0