Г)x^3-11x^2+28x=0 д)x^3+7x^2=18x е)5x^4-6x^3+x^2=0

X(x^2-11x+28) = 0
X=0      x^2-11x+28 =0
           D = 121 - 112 = 9= 3^2
           X1 = 7 X2=4

x^3+7x^2-18x = 0
x(x^2 +7x - 18) = 0
x=0    x^2+7x-18 = 0
         D = 49 +72 = 121 = 11^2

         x1 = 2 X2 = -9


5x^4-6x^3+x^2=0
X^2(5x^2 - 6x + 1) =0
x^2 =0      5x^2 - 6x +1 =0
x = 0        D = 36 -20 = 16 = 4^2
               x1 = 1    x2=0.2