Tìm $\large x$ biết: \(\large 16 \times x - 9 \times x = 21 \times 3

Tìm $\large x$ biết:

$\large 16 \times x - 9 \times x = 21 \times 3$

• A.

  $\large x$ = |

  9

$\large 16 \times x - 9 \times x = 21 \times 3$

$\large 7 \times x = 63$

$\large x = 63 : 7$

$\large x = 9$