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19 tháng 6 2018

8)\(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)

=\(\frac{4}{9}:\left(-\frac{1}{7}\right)+\frac{59}{9}:\left(-\frac{1}{7}\right)\)

=\(\left(\frac{4}{9}+\frac{59}{9}\right).\left(-7\right)\)

=7.(-7)

=-49

1: \(5\cdot3^x=5\cdot3^4\)

nên \(3^x=3^4\)

hay x=4

2: \(7\cdot4^x=7\cdot4^3\)

nên \(4^x=4^3\)

hay x=3

3: \(8\cdot7^x=8\cdot7^6\)

nên \(7^x=7^6\)

hay x=6

22 tháng 5 2022

5⋅3mũx=5⋅34

nên 3x=34

vậy x=4

2: 7⋅4x=7⋅43

nên 4x=43

vậy x=3

3: 8⋅7x=8⋅7mũ6⋅

nên 7x=76

20 tháng 6 2018

a/Ta có: \(\dfrac{4}{3}-\left[\left(\dfrac{-11}{6}\right)-\left(\dfrac{2}{9}+\dfrac{5}{3}\right)\right]\)

\(=\) \(\dfrac{4}{3}-\left[\dfrac{-11}{6}-\dfrac{2}{9}-\dfrac{5}{3}\right]\)

\(=\) \(\dfrac{4}{3}+\dfrac{11}{6}+\dfrac{2}{9}+\dfrac{5}{3}\)

\(=\) \(\dfrac{24}{18}+\dfrac{33}{18}+\dfrac{4}{18}+\dfrac{30}{18}\)

\(=\) \(\dfrac{91}{18}\)

b/Ta có: \(\left(8-\dfrac{9}{4}+\dfrac{2}{7}\right)-\left(-6-\dfrac{3}{7}+\dfrac{5}{4}\right)-\left(3+\dfrac{2}{4}-\dfrac{9}{7}\right)\)

\(=\) \(8-\dfrac{9}{4}+\dfrac{2}{7}+6+\dfrac{3}{7}-\dfrac{5}{4}-3-\dfrac{2}{4}+\dfrac{9}{7}\)

\(=\) \(8+6-3-\dfrac{9}{4}-\dfrac{5}{4}-\dfrac{2}{4}+\dfrac{2}{7}+\dfrac{3}{7}+\dfrac{9}{7}\)

\(=\) \(11-\dfrac{2}{4}+\dfrac{14}{7}\)

\(=\) \(11-\dfrac{1}{2}+2\)

\(=\) \(9-\dfrac{1}{2}\)

\(=\) \(\dfrac{17}{2}\)

Chúc bn học tốt!!!okokok

22 tháng 6 2018

phần b thầy mk chữa là = 9 đó

những dù sao cx thank youvui

20 tháng 9 2019

e) \(\frac{1}{7}.\frac{-3}{8}+\frac{-13}{8}.\frac{1}{7}\)

\(=\frac{1}{7}.\left[\left(-\frac{3}{8}\right)+\left(-\frac{13}{8}\right)\right]\)

\(=\frac{1}{7}.\left(-2\right)\)

\(=-\frac{2}{7}.\)

Chúc bạn học tốt!

29 tháng 9 2018

((3\(^2\)))\(^2\) - ((-5\(^2\)))\(^2\) + ((-2\(^3\)))\(^2\)

= 81 - 625 + 64

= -544+ 64

= -480

2\(^4\) + 8[(-2)\(^2\) :\(\dfrac{1}{2}\)]\(^0\) - 2\(^{-2}\). 4 + (-2)\(^2\)

= 16+ 8.1 - \(\dfrac{1}{4}\). 4 + 4

= 16+ 8- 1+4

= 27

2\(^4\) + 3(\(\dfrac{1}{2}\))\(^0\) + 2\(^{-2}\).8 + [(-2)\(^3\). \(\dfrac{1}{2^4}\)].2 - \(\dfrac{1}{2}\)

= 16 + 3.1 +\(\dfrac{1}{4}\).8 + [(-8).\(\dfrac{1}{16}\)].2 -\(\dfrac{1}{2}\)

= 16 + 3+ 2 + \(\dfrac{-1}{2}\).2- \(\dfrac{1}{2}\)

= 21 + (-1)- \(\dfrac{1}{2}\)

= 20-\(\dfrac{1}{2}\) = \(\dfrac{40}{2}\) - \(\dfrac{1}{2}\)= \(\dfrac{39}{2}\)

\(\dfrac{15^{10}.5^{10}}{75^{10}}\) + \(\dfrac{\left(0,8\right)^5}{\left(0,4\right)^6}\)

= \(\dfrac{\left(15.5\right)^{10}}{75^{10}}\) + \(\dfrac{\left(0,4.2\right)^5}{\left(0.4\right)^6}\)

= \(\dfrac{75^{10}}{75^{10}}\) + \(\dfrac{\left(0,4\right)^5.2^5}{\left(0,4\right)^6}\)

= 1 + \(\dfrac{2^5}{0,4}\) = 1+ 80 = 81

\(\dfrac{2^{13}.9^4}{6^3.8^3}\)

= \(\dfrac{2^{13}.\left(3^2\right)^4}{\left(2.3\right)^3.\left(2^3\right)^3}\) = \(\dfrac{2^{13}.3^8}{2^3.3^3.2^9}\)

= \(\dfrac{2^4.3^5}{2^3}\) = 2.3\(^5\) = 486

1 tháng 2 2024

Lalalalalalalalalalalalalalalala

15 tháng 9 2016

Cau a la 1

Cau b la 1215

Cau c la 768

Cau d la \(\frac{4185}{13}\)

15 tháng 9 2016

\(\frac{4^2.4^3}{2^{10}}=\frac{4^{2+3}}{\left(2^2\right)^5}=\frac{4^5}{4^5}=1\)

\(\frac{\left(0,6\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2.3\right)^5}{\left(0,2\right)^6}=\frac{\left(0,2\right)^5.3^5}{\left(0,2\right)^6}=\frac{3^5}{0,2}=1215\)

\(\frac{2^7.9^3}{6^5.8^2}=\frac{2^2.2^5.\left(3^2\right)^3}{\left(2.3\right)^5.\left(2^3\right)^2}=\frac{2^2.2^5.3^6}{2^5.3^5.2^6}=\frac{3}{2^4}=\frac{3}{16}\)

\(\frac{6^3+3.6^2+3^3}{-13}=\frac{2^3.3^3+3.\left(2.3\right)^2+3^3}{-13}=\frac{2^3.3^3+3.2^2.3^2+3^3}{-13}=\frac{3^3.\left(2^3+2^2+1\right)}{-13}=\frac{3^3.13}{-13}=\left(-3\right)^3=-27\)

17 tháng 8 2018

a,(=)\(3^{x+1}.\left(3+4\right)=7.3^6\)

(=)\(3^{x+1}=3^6\)

=>x+1=6(=)x=5

b

30 tháng 8 2019

1) -2/3

1: \(\Leftrightarrow3x+4=2\)

=>3x=-2

=>x=-2/3

2: \(\Leftrightarrow7x-7=6x-30\)

=>x=-23

3: =>\(5x-5=3x+9\)

=>2x=14

=>x=7

4: =>9x+15=14x+7

=>-5x=-8

=>x=8/5

Bài 1 :

a) \(-3+\left(-4\right)-\left(-3\right)+\left(2+7-10\right)=-3-4+3+2+7-10=-5\)

b) \(3-\left(-3+2-7\right)+\left(-4\right)=3+3-2+7-4=7\)

c) \(7+\left(-2-3+7\right)-\left(-2\right)=7-2-3+7+2=17\)

d) \(-\left(-3\right)-\left(-2+3-8\right)+\left(-6\right)=3+2-3+8-6=4\)

Bài 2 :

a) \(x^2-2x-\left(3x-2x\right)=x^2-2x-3x+2x=x^2-3x\)

b) \(-\left(x^2+3x^2\right)-\left(-5x^2+3x\right)=-x^2-3x^2+5x^2-3x=x^2-3x\)

c) \(\left(x-y\right)-\left(x+3y+1\right)=x-y-x-3y-1=-4y-1\)

23 tháng 6 2019

Bài 1:

a, -3+ (-4) - (-3) + (2 + 7 - 10)

= -3 - 4 + 3 + 2 + 7 - 10

= 5 - 10

= -5.

b, 3 - (-3 + 2 - 7) + (-4)

= 3 + 3 - 2 + 7 - 4

= 11 - 4

= 7

c, 7 + (-2 - 3 + 7) - (-2)

= 7 - 2 - 3 + 7 + 2

= 9 + 2

= 11.

d, - (-3) - (-2 + 3 - 8) + (-6)

= 3 + 2 - 3 + 8 - 6

= 10 - 6

= 4.

Mình chỉ làm bài 1 thôi nhé.

Chúc bạn học tốt!