câu 1; a) -11/14 +4/7 +1/2 b) -8/20+ 0,9 .(1/3- 1/5) :20%
câu 2: a) 1/3+1/3:x=-1/5 b) x-1/3.x=2 1/3
(hỗn số)
câu 1; a) -11/14 +4/7 +1/2 b) -8/20+ 0,9 .(1/3- 1/5) :20%
câu 2: a) 1/3+1/3:x=-1/5 b) x-1/3.x=2 1/3
(hỗn số)
Đáp án:
Câu 1:
a) `-\frac{11}{14}` + `\frac{4}{7}` + `\frac{1}{2}`
= `-\frac{11}{14}` + `\frac{8}{14}` + `\frac{7}{14}`
= `\frac{2}{7}`
b) `-\frac{8}{20}` `+` `0,9` . `(“\frac{1}{3}` `-` `\frac{1}{5}“)“:“20%`
= `-\frac{2}{5}` `+` `\frac{9}{10}` . `(“\frac{1}{3}` `-` `\frac{1}{5}“)“:“\frac{1}{5}`
= `-\frac{2}{5}` `+` `\frac{9}{10}` . `\frac{2}{15}“:“\frac{1}{5}`
= `-\frac{2}{5}` `+` `\frac{3}{25}“:“\frac{1}{5}`
= `-\frac{2}{5}` `+` `\frac{3}{5}`
= `\frac{1}{5}`
Cau 2:
a) `\frac{1}{3}` `+` `\frac{1}{3}` : `x` = `-\frac{1}{5}`
`\frac{1}{3}` : `x` = `-\frac{1}{5}` `-` `\frac{1}{3}`
`\frac{1}{3}` : `x` = `-\frac{8}{15}`
`x` = `\frac{1}{3}` :`-\frac{8}{15}`
`x` = `-\frac{5}{8}`
Vậy `x` = `-\frac{5}{8}`
b) `x` `-“\frac{1}{3}` .`x` = `2\frac{1}{3}`
`x`.`(“1“-“\frac{1}{3}“)` = `\frac{7}{3}`
`x`.`\frac{2}{3}` = `\frac{7}{3}`
`x` = `\frac{7}{3}`:`\frac{2}{3}`
`x` = `\frac{7}{2}`
Vậy `x` = `\frac{7}{2}`
#Jen_
Đáp án:
Câu 1:
a) 2/7
b) -8/20
Câu 2:
a) x=-5/8
b) x=7/2
Giải thích các bước giải:
Câu 1:
a)
-11/14 +4/7 +1/2
=-11/14 + 8/14 + 7/14
=(-11+8+7) / 14
= 2/7
b)
-8/20+ 0,9 .(1/3- 1/5) :20%
=-8/20 + 9/10.(1/3-1/5) : 1/5
=-8/20+9/10.(5/15 -3/15) : 1/5
=-8/20+9/10. 2/15 : 1/5
=-8/20 + 3/5
=1/5
Câu 2:
a)
1/3+1/3:x=-1/5
1/3 : x=(-1/5)-1/3
1/3 : x=(-3/15)-5/15
1/3 : x= -8/15
x=1/3 : (-8/15)
x=1/3 .-15/8
x=-5/8
b)
x-1/3.x=2 1/3
x(1- 1/3)= 7/3
x.2/3=7/3
x=7/3: 2/3
x= 7/2