1) 3 . x - 1 = 89. 2) 2 . ( x + 3) - 15 = 21

3.x - 1 = 89

2. ( x+3) -15 = 21

150- 50 . ( x – 2) = 100

3. ( x + 2) + 11 = 101

( x + 3): 4 = 25

100: ( x – 1) =25

96- 3. ( x+ 1) =42

( . là nhân)