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|
