Rút gọn P = | 3x - 3 | + 2x + 1

1)

a) P = \(\left|3x-3\right|+2x+1\)

+) Nếu \(3x-3\ge0\Rightarrow x\ge1\Rightarrow\left|3x-3\right|=3x-3\)

\(\Rightarrow P=3x-3+2x+1=5x-2\)

+) Nếu \(3x-3< 0\Rightarrow x< 1\Rightarrow\left|3x-3\right|=-3x+3\)

\(\Rightarrow P=-3x+3+2x+1=-x+4\)

Vậy P = 5x-2 khi x \(\ge1\) và P = -x+4 khi x < 1

b) P = 6

+) Nếu \(x\ge1\Rightarrow5x-2=6\Rightarrow x=1,6\)( thoả mãn )

+) Nếu x < 1 \(\Rightarrow-x+4=6\Rightarrow-x=2\Rightarrow x=-2\)(t/m)

Vậy P = 6 khi x = 1,6 hoặc x = -2

c) P = 2x+2

+) Nếu \(x\ge1\Rightarrow5x-2=2x+2\)

\(\Rightarrow3x=4\Rightarrow x=\dfrac{4}{3}\) (t/m)

+) Nếu x < 1 \(\Rightarrow-x+4=2x+2\)

\(\Rightarrow-3x=-2\Rightarrow x=\dfrac{2}{3}\)(t/m)

Vậy P = 2x+2 khi x = \(\dfrac{4}{3}\) hoặc x = \(\dfrac{2}{3}\)

d) P = | 2-x |

+) Nếu x \(\ge2\) \(\Rightarrow5x-2=2-x\)

6x = 4

x = \(\dfrac{2}{3}\)(không t/m)

+) Nếu x < 2 \(\Rightarrow\) -x + 4 = -2 + x

-2x = -6

x = 3 ( không t/m )

Vậy không có x thoả mãn P = |2-x|

m=(-1,2:(1 3/5x1,25) / 0,64 -1/25) +((1,08-2/25):4/ 7 /(5 5/9-9/4)x36/17)+0,6x0,5 :2/5