Question

Tính giá trị biểu thức

 -7/2 - (5/3)^2 : 10/27

a) -3/5 ×7/9 + (-3/5) × 2/9+3/5

c) tìm x biết: 1/2x - 2/3 =|-2 1/3|

Answer 1

\(-\dfrac{7}{2}-\left(\dfrac{5}{3}\right)^2:\dfrac{10}{27}\\ =-\dfrac{7}{2}-\dfrac{25}{9}:\dfrac{10}{27}\\ =-\dfrac{7}{2}-\dfrac{25}{9}.\dfrac{27}{10}\\ =-\dfrac{7}{2}-\dfrac{675}{90}\\ =-\dfrac{7}{2}-\dfrac{75}{9}\\ =-\dfrac{63}{18}-\dfrac{150}{18}\\ =-\dfrac{213}{18}\)

`a) -3/5 xx 7/9 + (-3/5) xx 2/9 + 3/5`

`=-3/5 xx (7/9+2/9) + 3/5`

`=-3/5 xx 1 + 3/5`

`=-3/5+3/5`

`=0`

Answer 2

Bổ sung : \(\dfrac{1}{2}x-\dfrac{2}{3}=\left|-2\dfrac{1}{3}\right|\\ \dfrac{1}{2}x-\dfrac{2}{3}=\left|-\dfrac{7}{3}\right|\\ \dfrac{1}{2}x-\dfrac{2}{3}=\dfrac{7}{3}\\ \dfrac{1}{2}x=\dfrac{7}{3}+\dfrac{2}{3}\\ \dfrac{1}{2}x=\dfrac{9}{3}\\ \dfrac{1}{2}x=3\\ x=3:\dfrac{1}{2}\\ x=3.2\\ x=6\)