1) tính
a) -4/7.7/-16
=1/4
b)-5/16 . ( -32)
=10
c)(-3/5 )^2
=9/25
d) ( 1- 1/5 ). ( 3/10 + 1/5 )
=4/5.1/2
=2/5
2) tìm x:
a)7/3 +x = -14/5
x=-14/5- 7/3
x=7/15
b) x+ 1/3 = 7/26 . -13/6
x+ 1/3=-7/12
x=-7/12 - 1/3
x=-11/12
3) tính:
a) 1/3 . 3/7 .5/11
=1/7 . 5/11
=5/77
b) -13/19 . 1/12 + -13/18 . 11/12
=-13/228 + (-143/216)
=-2951/4104
c) 17/31 . -5/19 + -17/31 . 5/19
=-85/589 + -85/589
=-170/589
CHÚC BẠN HỌC TỐT
CHO MK 5 SAO + TLHN NHÁ
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