`a)` `3 . 5^2 + 15 . 2^2 - 26 : 2`

`= 3 . 25 + 15 . 4 - 13`

`= 75 + 60 - 13`

`= 135 - 13`

`= 122.`

`-----------`

`b)` `2021 + 5 . [ 300 - (17 - 7)^2 ]`

`= 2021 + 5 . ( 300 - 10^2 )`

`= 2021 + 5 . ( 300 - 100 )`

`= 2021 + 5 . 200`

`= 2021 + 1000`

`= 3021.`

`-----------`

`c)` `3^2 .5 + 2^3 . 10 - 81 : 3`

`= 9 . 5 + 8 . 10 - 27`

`= 45 + 80 - 27`

`= 125 - 27`

`= 98.`

`-----------`

`d)` `( 5^19 : 5^17 + 3 ) : 7`

`= ( 5^2 + 3 ) : 7`

`= ( 25 + 3 ) : 7`

`= 28 : 7`

`= 4.`

`-----------`

`f)` `128 . 46 + 128 . 32 + 128 . 22`

`= 128 . ( 46 + 32 + 22 )`

`= 128 . 100`

`= 12800.`

         $\color{turquoise}{\text #Icyne}$  

 $\text{ CHÚC BẠN HỌC TỐT! }$