Đáp án:
a) M=3x−4M=3x−4
b) N=2x+5N=2x+5
Giải thích các bước giải:
a) Vì x>1,5⇒2x−3>0;x−1>0x>1,5⇒2x−3>0;x−1>0
M=2x−3+x−1=3x−4M=2x−3+x−1=3x−4
b) Vì x<−1⇒x+1<0;2−x>0x<−1⇒x+1<0;2−x>0
N=2−x+3x+3=2x+5N=2−x+3x+3=2x+5
c)
TH1: x>2x>2 ta có: P=3x−5+x−2=4x−7P=3x−5+x−2=4x−7
TH2: x<53x<53 ta có: P=5−3x+2−x=7−4xP=5−3x+2−x=7−4x
TH3: 53≤x≤253≤x≤2 ta có: P=3x−5+2−x=2x−3P=3x−5+2−x=2x−3
d)
TH1: x>3x>3 ta có: Q=x−3−2.5.x=−9x−3Q=x−3−2.5.x=−9x−3
TH2: x<0x<0 ta có: Q=3−x+10.x=9.x+3Q=3−x+10.x=9.x+3
TH3: 0≤x≤30≤x≤3 ta có: P=3−x+10.x=3−9.x
