Đáp án:
Giải thích các bước giải:
Bài 1
a,1-1/2-1/3=6-3-2/6=1/6
b,2/5+3/5:9/10=2/5+2/3=16/15
c,7/11.3/4+7/11.1/4+4/11=7/11.(3/4+1/4)+4/11=7/11.1+4/11=1
d,(3/4+0,5+25%)2 2/3=(3/4+1/2+1/4)8/3=3/2.8/3=4
Bài 2
a,x+1/2=2⇒x=2-1/2=3/2
b,75%x-1/2=-1 1/4⇔3/4x-1/2=-5/4
3/4x=-5/4+1/2=-3/4
⇒x=-3/4:3/4=-1
c,║x-2/5║+7/10=3
║x-2/5║=3-7/10=23/10
*)x-2/5=23/10⇒x=23/10+2/5=27/10
*)-(x-2/5)=23/10⇒x=23/10-2/5=-19/10
