1:Tính A=\(\sqrt{4+\sqrt{7}}\)-\(\sqrt{4-\sqrt{7}}+\left(\sqrt{3}+1\right)\sqrt{6+2\sqrt{2}\sqrt{3-\sqrt{\sqrt{2}+\sqrt{12}+\sqrt{18-\sqrt{128}}}}}\)

B1:cho a,b,c khác 0 thoả mãn ab+ac+bc=0. Tính A=\(\frac{bc}{a^2}\)+\(\frac{ac}{b^2}\)+\(\frac{ab}{c^2}\)