-84 : 4 + 3⁹ : 3⁷ + 5⁰

= -21 + 3² + 1

= -21 + 9 + 1

= -21 + 10

= -11

Đáp số : -11

-84:4+3^9;3^7+5^0

= -11

Chúc bạn may mắn!

\(-84:4+3^9:3^7+5^0\)

\(=-21+3^2+1\)

\(=-21+9+1\)

\(=-12+1\)

\(=-11\)

=21+9+1=31

84:4+3^9 : 3^7 + 5^0 

= 84:4 + 3^2 +1

=84:4+9+1

=21+9+1

=30+1

=31

Mk làm đúng thì k và kb nha , Poi 

a)-84:4+3^9:3^7+5^0

=-21+(3^9:3^7)+1

=-21+3^2+1

=-21+9+1

=-12+1

=-11

b)295-(31-2^5.5)^2

=295-(31-32.5)^2

=295-(-129)^2

=295+129^2

=295-16641

=-16346

tick cho mk nha bạn

a) -84 : 4 + 3^ 9 : 3 ^ 7 + 5 ^0

=-84:4+3^2+1

=-84:4+9+1

=-21+9+1

=-12+1

=-11

b) 295 - ( 31 - 2^ 5. 5) ^2

= 295 - ( 31 -32. 5)^2

= 295 - (-129)^2

=295-16641

=-16346

a)- 11

b) - 16346

a) \(x.3,9+x.0,1=2,7\)

x . (3,9+0,1) = 2,7

x . 4 = 2,7

x = 2,7 : 4

x = 0,675

b) x.3 + x.5 = 9,84

x . ( 3+5) = 9,84

x . 8 = 9,84

x = 9,84 : 8

x = 1,23

c) 12,3:x - 4,5:x = 15

(12,3-4,5) : x = 15

7,8 : x = 15

x = 7,8 : 15

x = 0,52

d) 7.x - 2.x = 1,85

(7-2) . x = 1,85

5 . x = 1,85

x = 1,85 : 5

x = 0,37

a)(-57)+(-159)+47+169=[(-57)+47]+[(-159)+169]=(-10)+10=10

b)84:4+3^9:3^7+5^0=21+3^2+1=21+9+1=31

a,3.52+(15.22-23.22)

= 156 + 22(15 - 23)

= 156 + 22. (-8)

= 156 - 176

= -20

b,75.34+76.75-75.10

= 75(34 + 76 - 10)

= 75. 100

= 7500

c,84:4+3 mũ 9 : 3 mũ 7 +2017 mũ 0

= 84 : 4 + 3⁹ : 3⁷ + 2017⁰

= 21 + 9 + 1

= 31

a) Ta có: \(3\cdot52+\left(15\cdot22-23\cdot22\right)\)

\(=3\cdot52+22\cdot\left(15-23\right)\)

\(=3\cdot52+22\cdot\left(-8\right)\)

\(=156-176=-20\)

b) Ta có: \(75\cdot34+76\cdot75-75\cdot10\)

\(=75\cdot\left(34+76-10\right)\)

\(=75\cdot\left(110-10\right)\)

\(=75\cdot100\)

\(=7500\)

c) Ta có: \(84:4+3^9:3^7+2017^0\)

\(=21+3^{9-7}+1\)

\(=22+3^2\)

\(=22+9=31\)

1. \(\dfrac{2019}{2020}-\left(\dfrac{2019}{2020}-\dfrac{2020}{2021}\right)\)

\(=\dfrac{2019}{2020}-\dfrac{2019}{2020}+\dfrac{2020}{2021}\)

\(=0+\dfrac{2020}{2021}=\dfrac{2020}{2021}\)

Giải:

1) \(\dfrac{2019}{2020}-\left(\dfrac{2019}{2020}-\dfrac{2020}{2021}\right)\)  

\(=\dfrac{2019}{2020}-\dfrac{2019}{2020}+\dfrac{2020}{2021}\) 

\(=\left(\dfrac{2019}{2020}-\dfrac{2019}{2020}\right)+\dfrac{2020}{2021}\) 

\(=0+\dfrac{2020}{2021}\) 

\(=\dfrac{2020}{2021}\) 

2) \(\dfrac{2}{9}+\dfrac{7}{9}:\left(\dfrac{42}{5}-\dfrac{7}{5}\right)\) 

\(=\dfrac{2}{9}+\dfrac{7}{9}:7\) 

\(=\dfrac{2}{9}+\dfrac{1}{9}\) 

\(=\dfrac{1}{3}\) 

3) \(\dfrac{3}{4}+\dfrac{x}{4}=\dfrac{5}{8}\) 

            \(\dfrac{x}{4}=\dfrac{5}{8}-\dfrac{3}{4}\) 

            \(\dfrac{x}{4}=\dfrac{-1}{8}\)  

\(\Rightarrow x=\dfrac{4.-1}{8}=\dfrac{-1}{2}\) 

4) \(\left|3x+1\right|-\dfrac{1}{4}=\dfrac{-1}{4}\) 

            \(\left|3x-1\right|=\dfrac{-1}{4}+\dfrac{1}{4}\) 

            \(\left|3x-1\right|=0\) 

             \(3x-1=0\) 

                    \(3x=0+1\) 

                    \(3x=1\) 

                      \(x=1:3\) 

                      \(x=\dfrac{1}{3}\) 

Chúc bạn học tốt!

4) \(\left|3x+1\right|-\dfrac{1}{4}=\dfrac{-1}{4}\) 

            \(\left|3x+1\right|=\dfrac{-1}{4}+\dfrac{1}{4}\) 

            \(\left|3x+1\right|=0\) 

              \(3x+1=0\) 

                    \(3x=0-1\) 

                    \(3x=-1\) 

                      \(x=-1:3\) 

                      \(x=\dfrac{-1}{3}\)