a. 43 x 17 + 29 x 57 + 13 x 43 + 57 b. 3 x 8 x 25 + 4 x 6 x37 + 2 x 12 + 28

Đáp án:

$\text{a) 3000.}$

$\text{b) 1540.}$

Giải thích các bước giải:

$\text{a) 43 × 17 + 29 × 57 + 13 × 43 + 57.}$

$\text{= (43 × 17 + 13 × 43) + (29 × 57 + 57).}$

$\text{= 43 × (17 + 13) + 57 × (29 + 1).}$

$\text{= 43 × 30 + 57 × 30.}$

$\text{= (43 + 57) × 30.}$

$\text{= 100 × 30.}$

$\text{= 3000.}$

$\text{b) 3 × 8 × 25 + 4 × 6 × 37 + 2 × 12 + 28.}$

$\text{= 24 × 25 + 24 × 37 + 24 + 28.}$

$\text{= 24 × (25 + 37 + 1) + 28.}$

$\text{= 24 × 63 + 28.}$

$\text{= 1512 + 28.}$

$\text{= 1540.}$