a) $\sqrt{25}$ -$\frac{390^3}{130^3}$ b)-3,75 .(-7,2) +2,8 .3,75 c) $\frac{-6}{9}$ +$\frac{-3}{4}$

Đáp án:

`a)`

` \sqrt(25) – (390^3)/(130^3)`

` = 5 – (390/130)^3`

` = 5- 3^3`

` = 5 – 27`

` = -22`

`b)`

` -3,75 * (-7,2) + 2,8 * 3,75`

` = 3,75 * 7,2 + 2,8 * 3,75`

 ` = 3,75 ( 7,2 + 2,8 )`

` = 3,75 * 10`

` = 37,5`

`c)`

` -6/9 + -3/4`

` = -2/3  -3/4`

` = -8/12 – 9/12`

` = (-8-9)/12`

` = -17/12`