Question

[pham thi ngoc]

Tìm x bt

1) 3.(2x−1).(3x−1)−(2x−3).(9x−1)−3=−3

2) 3x−1.(2x+7)−x+1.(6x−5)=x+2−(x−5)

3) 3xy.(x+y)−(x+y).(x2+y2+2xy)+y3=27

4) 5.x+1.(1−x).(2x2+3)=0

giúp mk vs mai mk đi hk rù

Answer 1

[Nguyễn Lê Phước Thịnh]

1: \(\Leftrightarrow3\left(6x^2-5x+1\right)-\left(18x^2-29x+3\right)=0\)

\(\Leftrightarrow18x^2-15x+3-18x^2+29x-3=0\)

=>x=0

2: \(\Leftrightarrow3x-2x-7-x+6x-5=x+2-x+5=7\)

=>6x-12=7

=>6x=19

hay x=19/6