tính 3x5x9/18x5x3= ..................... 30x25x7x8/ 75x8x12x14=......................... 8x10x5x9x7/ 16x20x15x3=...................... 50x15x7x8/25x45x49x4=....................... giúp mik lm vào giấy vs ạ

Đáp án:

`(3×5×9)/(18×5×3)`

`=(3×5×9)/(2 × 9×5×3)`

`=(\cancel3×\cancel5×\cancel9)/(2 × \cancel9×\cancel5×\cancel3)`

`= 1/2`

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

`(30×25×7×8)/(75×8×12×14)`

`= (2 × 15 × 25 × 7 × 8)/(3 × 25 × 8 × 2 × 6 × 2 × 7)`

`= (2 × 3 ×5 × 25 × 7 × 8)/(3 × 25 × 8 × 2 × 6 × 2 × 7)`

`= (\cancel2 × \cancel3 ×5 × \cancel25 × \cancel7 × \cancel8)/(\cancel3 × \cancel25 × \cancel8 × \cancel2 × 6 × 2 × \cancel7)`

`= 5/(6 × 2)`

`= 5/12`

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

`(8×10×5×9×7)/(16×20×15×3)`

`= (8×10×5×3×3×7)/(8×2×2×10×5×3×3)`

`=(\cancel8×\cancel10×\cancel5×\cancel3×\cancel3×7)/(\cancel8×2×2×\cancel10×\cancel5×\cancel3×\cancel3)`

`= 7/(2 xx 2)`

`= 7/4`

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

`(50×15×7×8)/(25×45×49×4)`

`= (25 × 2 × 15 × 7 × 2 × 4)/(25 × 3 × 15 × 7 × 7 × 4)`

`= (\cancel25 × 2 × \cancel15 × \cancel7 × 2 × \cancel4)/(\cancel25 × 3 × \cancel15 × \cancel7 × 7 × \cancel4)`

`= (2 xx 2)/(3 xx 7)`

`= 4/21`

$@dariana$