Question

Giúp mik làm bài náy vs:

1.  Tìm x:

| 2x + 3 | - 2| 4-x | = 5

Answer 1

\(\left|2x+3\right|-2\left|4-x\right|=5\)

\(\Rightarrow\left|2x+3\right|-\left|8-2x\right|=5\)

\(\Rightarrow\left|2x+3\right|=5+\left|8-2x\right|\)

+) \(TH_1:2x+3\ge0\Rightarrow2x\ge3\Rightarrow x\ge\frac{3}{2}\)

\(2x+3=5+8-2x\)

\(\Rightarrow2x+2x=-3+13\)

\(\Rightarrow4x=10\)

\(\Rightarrow x=\frac{5}{2}.\)

+) \(TH_2:2x+3< 0\Rightarrow2x< -3\Rightarrow x< \frac{-3}{2}\)

\(-2x-3=5+8-2x\)

\(\Rightarrow-2x+2x=3+13\)

\(\Rightarrow0=16\) (vô lí)

Vậy \(x=\frac{5}{2}.\)

Answer 2

l2x+3l-2l4-xl=5

nên x=2.5

Answer 3

nhưng còn cách làm

Answer 4

x=2.5 nha