B

b

"Can you play the piano, Hung"

→The teacher asked Hung if could phay the piano

"How many book do you have,children?"

→He asked children how many book they had

"Where do you live, Lan"

→He asked Lan where she lived 

|3x+5x|-2x=9-3x

=>|8x| = 9 - x  

TH1: x ≥ 0

=> |8x| = 8x

=> |8x| = 9 - x  <=> 8x = 9 - x

<=> 9x = 9

<=> x = 1 (TM)

TH2: x < 0

=> |8x| = -8x

=> (1) <=> -8x = 9 - x

<=> -7x = 9

<=> x = -9/7 (TM)

vậy x ∊ {1; -9/7}

B/  có 2cách