drakerton 1) х*(х+5)=(х+3)^2
x^2 + 5x = x^2 + 6x +9 
- x -9 = 0
- x = 9
x = -9 
2) х(х(х-1))+6=х(х+3)*(х-4)
x(x^2-x)) + 6 = х^2+3x*(х-4)
x^3 - x2 +6 = x^3 - 4x^2 + 3x^2 -12x
x^3 - x^3 - x^2 + 4x^2 - 3x^2 + 12x+6 = 0
12x + 6 = 0
12x = -6
x = -0,5