A. X + 15 = 20 B. X – 18 = 16X = 20 – 15 X = 16 + 18X = 5 X = 34...

Câu 1.a. x + 15 = 20 b. x – 18 = 16x = 20 – 15 x = 16 + 18x = 5 x = 34c. 72 – x = 50 d. x ⨯ 7 = 42x = 72 – 50 x = 42 : 7x = 22 x = 6e. x : 7 = 5 g. 49 : x = 7x = 5⨯ 7 x = 49 : 7x = 35 x = 7h. 36 - x = 14 i. 24 : x = 6x = 36 - 14 x = 24 : 6x = 22 x = 4k. 28 : x = 7x = 28 : 7x = 4