$\text{b, 58 × 42 + 32 × 8 + 5 × 16}$
$\text{= 58 × 42 + 16 × 2 × 8 + 5 × 16}$
$\text{= 58 × 42 + 16 × (2 × 8 + 5)}$
$\text{= 58 × 21 × 2 + 16 × 21}$
$\text{= 21 × (58 × 2 + 16)}$
$\text{= 21 × 132}$
$\text{= 2772}$
$\text{c, (42 × 43 + 43 × 57 + 1) - 360 : 4}$
$\text{= 43 × (42 + 57 + 1) - 90}$
$\text{= 43 × 100 - 90}$
$\text{= 4300 - 90}$
$\text{= 4210}$
7.
$\text{a, 890 : x = 35 (dư 15)}$
$\text{x = (890 - 15) : 35}$
$\text{x = 875 : 35}$
$\text{35}$
$\text{b, 648 - 34 × x = 444}$
$\text{34 × x = 648 - 444}$
$\text{34 × x = 204}$
$\text{x = 204 : 24}$
$\text{x = 6}$
$\text{1482 : x + 23 = 80}$
$\text{1482 : x = 80 - 23}$
$\text{1482 : x = 57}$
$\text{x = 1482 : 57}$
$\text{x = 26}$
$\text{* Xl bn, mik đăng bài muộn quá vì phải vào bếp ăn trưa. mong bạn cho mik hay nhất *}$
