thu gon bieu thuc sau a) x (2x^2-3)-x^2 (5x+1)+x^2 b)3x (x-2)-5x (1-x)-8 (x^2-3) c)(x+3) (x^2-3x+9)-(54+x^3) d) (2x+y) (4x^2-2xy+y^2)-(4x^2+2xy+y^2)
thu gon bieu thuc sau a) x (2x^2-3)-x^2 (5x+1)+x^2 b)3x (x-2)-5x (1-x)-8 (x^2-3) c)(x+3) (x^2-3x+9)-(54+x^3) d) (2x+y) (4x^2-2xy+y^2)-(4x^2+2xy+y^2)