Question

Tìm x biết:

1) | 2x-1| = -19 -x

2) | 4- 3x| = 2x- 10

3) | x| = 3+ 2x

Answer 1

1) |2x-1|=-19-x<=> \(\left[\begin{array}{nghiempt}2x-1=-19-x\\2x-1=19+x\end{array}\right.\)=> x=-6 hoặc x=20

2) |4-3x|=2x-10<=>\(\left[\begin{array}{nghiempt}4-3x=2x-10\\4-3x=10-2x\end{array}\right.\)=> x= 14/6 hoặc x=-6

3) |x|=3+2x<=> \(\left[\begin{array}{nghiempt}x=-3-2x\\x=3+2x\end{array}\right.\)=> x=-1 hoặc x=-3

Answer 2

1) - Nếu 2x - 1 < 0 thì -2x + 1 = -19 - x => -x = -20 => x = 20

    - Nếu 2x - 1 > 0 thì 2x - 1 = -19 - x => 3x = -18 => x = -6

2) - Nếu 4 - 3x < 0 thì -4 + 3x = 2x - 10 => 6 = -x => x = -6

    - Nếu 4 - 3x > 0 thì 4 - 3x = 2x - 10 => 14 = 5x => x = \(\frac{14}{5}\)

3) - Nếu x < 0 thì -x = 3 + 2x => -3x = 3 => x = -1

    - Nếu x > 0 thì x = 3 + 2x => -x = 3 => x = -3