Toán Giải biểu thức: A = ($1-\sqrt[]{7}$) x $\frac{\sqrt[]{7}+7}{2\sqrt[]{7}}$ 18/07/2021 By Hailey Giải biểu thức: A = ($1-\sqrt[]{7}$) x $\frac{\sqrt[]{7}+7}{2\sqrt[]{7}}$
A =(1-$\sqrt[]{7}$ ).$\frac{\sqrt[]{7}+7}{2\sqrt[]{7}}$ =(1-$\sqrt[]{7}$ ).$\frac{\sqrt[]{7}(1+\sqrt[]{7})}{2\sqrt[]{7}}$ =.$\frac{\sqrt[]{7}(1+\sqrt[]{7})(1-\sqrt[]{7} )}{2\sqrt[]{7}}$ =$\frac{1-7}{2}$ =$\frac{-6}{2}$ =-3 Vậy A =-3 Trả lời
A =(1-$\sqrt[]{7}$ ).$\frac{\sqrt[]{7}+7}{2\sqrt[]{7}}$
=(1-$\sqrt[]{7}$ ).$\frac{\sqrt[]{7}(1+\sqrt[]{7})}{2\sqrt[]{7}}$
=.$\frac{\sqrt[]{7}(1+\sqrt[]{7})(1-\sqrt[]{7} )}{2\sqrt[]{7}}$
=$\frac{1-7}{2}$
=$\frac{-6}{2}$
=-3
Vậy A =-3
(1-√7) x $\frac{√7+7}{2√7}$
=(1-√7)$\frac{√7(1+√7)}{2√7}$
=(1-√7)(1+√7)/2
=-6/2
=-3