Đáp án:
Giải thích các bước giải:
Câu 1
a)(-3/5)>(-4/5)
b)(-4/5)>(-9/10)
Câu 2
a)4/5+(-5/6)=24/30+(-25/30)=-1/30
b)5/9.(-4/7)=35/63.(-36/63)=-1/63
d)-1,4.15/49-(80%+2/3):21/5
=-14/10.15/49-(8/10+2/3):21/5
=-14/10.15/49-(24/30+20/30):21/5
=-14/10.15/49-44/30:21/5
=-21/49-220/63
=1323/3087-1078/3087
=245/3078
Câu 3
a)x+1/3=-1/5
x =1/5-1/3
x =3/15- 5/15
x =-2/15
Vậy x=-2/15
b)-3/4:x=1/2
x=-3/4:1/2
x=-6/4
Vậy x=-6/4