1) x: (3+x) + 4x+6: (x^2+4x+3) = 0

2)

a) 2x+1 / (x-3) ≤ 1

b) (x-2) (x+5) : (x-1) ^2

x^3 - 3x^2 - 4x = 0,

x (x^2-3x-4) = 0,

x1=0,

x^2-3x-4=0,

x2=-1, x3=4;

(2x - 1) ^4 - x^2 = 0,

((2x-1) ^2) ^2-x^2=0,

((2x-1) ^2-x) ((2x-1) ^2+x) = 0,

(2x-1) ^2-x=0,

4x^2-5x+1=0,

D=9,

x1=1/4, x2=1;

(2x-1) ^2+x=0,

4x^2-3x+1=0,

D=-7<0; нет решений

x^3 - 3x^2 - x + 3 = 0,

x^2 (x-3) - (x-3) = 0,

(x-3) (x^2-1) = 0,

x-3=0, x1=3;

x^2-1=0, x^2=1, x2=-1, x3=1