3х²=2х+4
3х²-2х-4=0
D = (-2)2 - 4·3·(-4) = 52
x1 = (2 - √52)/2*3 = 1/3 - 1/3√13 ≈ -0.86852
x2 = (2 + √52)/2*3 = 1/3 + 1/3√13 ≈ 1.5352
(х-1)(2х+3)=-2
2х²+3х-2х-3+2=0
2х²+х-1=0
D = 12 - 4·2·(-1) = 9
x1 = (-1 - √9)/2*2 = -1
x2 = (-1 + √9)/2*2 = 0.5
(Х²+7)/2=4Х
Х²+7=8Х
Х²-8Х+7=0
D = (-8)2 - 4·1·7 = 36
x1 = (8 - √36)/2 = 1
x2 = (8 + √36)/2 = 7