MỖI Ý 1Đ438152227 +9 ¿ X = 7 =

9 :

7

b.

a. X +

3

4

X + ³ ₇ ^{= 28} ₉

9

X = ¹¹ 9

X = ²⁸ ₉ ^{− 3} ₇

X = ¹¹ ₉ ^{: 4} ₉

X = ¹⁶⁹ ₆₃

X = ¹¹ ₄