Tính: a. 3/7+(-5/2)+(-3/5) b. -8/18-15/27 c.4/5-(-2/7)-7/10 d. 3,5-(-2/7) Giúp mình với nhé. Các bạn làm ra giấy rồi chụp gửi mình cũng được

Đáp án:

 

Giải thích các bước giải:

 bài 1

a)3/7+(-5/2)+(-3/5)

=30/70+(-175/70)+(-42/70)

=-145/70+(-42/70)

=-187/70

b)-8/18-15/27

=-4/9-5/9

=-1

c)4/5-(-2/7)-7/10

=4/5+2/7-7/10

=56/70+20/70-49/70

=76/70-49/70

=27/70

d)3,5-(-2/7)

=3,5+2/7

=7/2+2/7

=49/14+4/14

=53/14

Bài 2

a)(-6/21).3/2

=-3/7.1/1

=-3/7

b)(-3).(-7/2)

=21/2

c)(11/12÷33/16).3/5

=(11/12.16/33).3/5

=(1/3.4/3).3/5

=4/9.3/5

=12/45

d)√(-7)²+√25/16-3/2

=-7+5/4-3/2

=-28/4+5/4-6/4

=-23/4-6/4

=-29/4

e)1/2.√100-√1/16+(1/3)^0

=1/2.10-1/4+1

=5-1/4+1

=20/4-1/4+4/4

=23/4

Bài 3

a)(9/25-2.18)÷(3'4/5+0,2)

=(9/25-16)÷(19/5+1/5)

=(9/25-400/25) ÷4

=-391/25÷4

=-25/391.4

=-100/391

b)3/8.19'1/3-3/8.33'1/3

=3/8.58/3-3/8.100/3

=3/8.(58/3-100/3)

=3/8.(-14)

=-42/8

c)1'4/23+5/21-4/23+0,5+16/21

=(1'4/23-4/23)+(5/21+16/21)+0,5

=1+1+0,5

=2,5

Bài 4

a)21/47+9/45+26/47+4/5

=(21/47+26/47)+(9/45+4/5)

=1+(1/5+4/5)

=1+1

=2

b)15/12+5/13-3/12-18/3

=(15/12-2/12)+(5/13-18/13)

=1+(-1)

=0

c)13/25+6/41-38/25+35/41-1/2

=(23/25-38/25)+(6/41+35/41)-1/2

=-1+1-1/2

=-1/2

d)12.(-2/3)²+4/3

=12.4/9+4/3

=4.4/3+4/3

=16/3+4/3

=19/3

e)12,5.(-5/7)+1,5.(-5/7)

=-5/7.(12,5+1,5)

=-5,7.14

=-10

f)4/5.(7/2+1/4)²

=4/5.(14/4+1/4)²

=4/5.(15/4)²

=4/5.225/16

=1/1.45/4

=45/4

Bài 5

a)(3/7+1/2)²

=(6/14+7/14)²

=(13/14)²

=169/196

b)(3/4-5/6)²

=(9/12-10/12)²

=(-1/12)²

=1/144

c)5^4.20^4/25^5.4^5

=(5.20)^4/(25.4)^5

=100^4/100^5

=1/100