a) cho x=\(1+\sqrt[3]{2}\) tính B = \(x^4-2x^5+x^3-3x^2+1942\)
b) cho x = \(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\) tính P =\(\dfrac{x^4-4x^3+x^2+6x+12}{x^2-2x+12}\)
c) cho x = \(1+\sqrt[3]{2}\)\(+\sqrt[3]{4}\) tính C = \(x^5-4x^4+x^3-x^2-2x+2015\)