a) (x-3)*(x+1) = x^2 + x -3x -3 = x^2 - 2x -3
б) (2x^2+3y^2)*(y^2-3x^2) = 2x^2y^2 - 6x^5 + 3y^4 - 9x^2y^2 = -7x^2y^2 - 6x^5+ 3y^4
в) (b+1)*(b^2-b+3) = b^3 - b^2 + 3b + b^2 - b + 3 = b^3 + 2b + 3
a) (x-3)*(x+1) = x^2 + x -3x -3 = x^2 - 2x -3
б) (2x^2+3y^2)*(y^2-3x^2) = 2x^2y^2 - 6x^5 + 3y^4 - 9x^2y^2 = -7x^2y^2 - 6x^5+ 3y^4
в) (b+1)*(b^2-b+3) = b^3 - b^2 + 3b + b^2 - b + 3 = b^3 + 2b + 3