1. (-∞; -4)∪(2;3); б) [-11;12] ; b) (-∞; -8)∪(4;+∞);
2х+5=0
2х=0-5
2х=-5
х=-5÷2
х=-2,5
Х 0 1 2
----------------------
у 0 -2 -4
X²+2x-3=0 a=1; b=2; c=-3
D= b²-4ac = 4-4·(-3) = 4+12 = 16 = 4²
x1 = (-b-√D)÷2a = (-2-4)÷(2·1) = -6÷2 = -3
x2 = (-b+√D)÷2a = (-2+4)÷(2·1) = 2÷2 = 1