（3-x)^2+4x(x-3)=0 ,5x^2 -18x+9=0, (5x-3)(x-3)=0, x1= 3/5, x2=3
9(x-2)^=4(x+1)^ 2, 5x^2 -44x +32=0, (5x-4)(x-8)=0, x1=4/5,x2=8
(2x-1)^-x^-4x-4=0, 3x^2 -8x -3=0, (3x+1)(x-3)=0, x1= -1/3, x2=3
x^-13x+12=42, x^2 -13x - 30=0, (x -15)(x+2)=0, x1=15,x2=-2