а) 5x^2*(-3x^3)^2= -15x^2*x^6=-15x^8
b) = 4x^2-4x+1+4x^2-1=-4x
x^(6*b)*(20*3^(2*b)*(-1)^(6*b)*x^4-20*3^(2*b)*(-1)^(6*b)*x^3+5*3^(2*b)*(-1)^(6*b)*x^2)+4*x^2-1
