Question

Решите неравенство
(5х-2)(х+2)≥0

Answer 1

5x^2+10x-2x-4 >=0
5x^2+8x-4>=0
5x^2+8x-4=0
D=64+80=144
x1=0,4
x2=-10 - посторонний корень

Answer 2

5x^2+10x-2x-4=0
5x^2+8x-4=0
D=64+99=144=12^2
x1=-8+12/10 =0.4
x2=-8-12/10=-2