\(A=3^{100}-3^{99}+3^{98}-...-3+1\\ \Rightarrow\dfrac{1}{3}A=3^{99}-3^{98}+3^{97}-...-1+\dfrac{1}{3}\\ \Rightarrow\dfrac{4}{3}A=3^{100}+\dfrac{1}{3}\\ \Rightarrow A=\dfrac{3^{101}}{4}+\dfrac{1}{4}\)

\(\dfrac{x}{3}-\dfrac{1}{4}=-\dfrac{5}{6}:\dfrac{1}{2}\\ \Rightarrow\dfrac{x}{3}-\dfrac{1}{4}=-\dfrac{5}{6}\cdot2\\ \Rightarrow\dfrac{x}{3}-\dfrac{1}{4}=-\dfrac{10}{6}\\ \Rightarrow\dfrac{x}{3}=-\dfrac{5}{3}+\dfrac{1}{4}\\ \Rightarrow\dfrac{x}{3}=-\dfrac{20}{12}+\dfrac{3}{12}\\ \Rightarrow\dfrac{x}{3}=-\dfrac{17}{12}\\ \Rightarrow12x=-17\cdot3\\ \Rightarrow12x=-51\\ \Rightarrow x=-\dfrac{17}{4}\)

x/3-1/4=5/3

      x/3=5/3+1/4

      x/3=21/12

  4x/12=21/12

       4x=21

         x=21/4

Bộ 3 số tự nhiên a, b, c chỉ có \(\left\{32;33;34\right\}\) thỏa mãn yêu cầu đề bài

Vế 2 thiếu dấu " ( " bạn ơi.

\(12\left(x+5\right)+2x=130\\\Leftrightarrow 12x+60+2x=130\\ \Leftrightarrow14x=70\\ \Leftrightarrow x=5\\ ----\\ 23\left(x-5\right)-12x=138\\ \Leftrightarrow23x-115-12x=138\\ \Leftrightarrow23x-12x=138+115\\ \Leftrightarrow11x=253\\ \Leftrightarrow x=\dfrac{253}{11}=23\\ ----\\ 360-12x+23\left(x-5\right)=278\\ \Leftrightarrow360-12x+23x-115=278\\ \Leftrightarrow-12x+23x=278+115-360\\ \Leftrightarrow11x=33\\ \Leftrightarrow x=\dfrac{33}{11}=3\)

\(6\left(x+3\right)+3\left(x-5\right)=278\\ \Leftrightarrow6x+18-3x-15=278\\ \Leftrightarrow6x-3x=278+15-18\\ \Leftrightarrow3x=275\\ \Leftrightarrow x=\dfrac{275}{3}\\ ---\\ \left(7-x\right)\left(3x-90\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}7-x=0\\3x-90=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=7\\x=30\end{matrix}\right.\)

89,6 x Y + Y : 10 + 10,3 x Y = 75,6

89,6 x Y + Y x 0,1 + 10,3 x Y = 75,6

Y x (89,6+0,1+10,3)=75,6

Y x 100 = 75,6

Y= 75,6:100

Y= 0,756

Cám ơn Dương nhé 😍

Bài 4:

\(a,2^{30}=\left(2^3\right)^{10}=8^{10};3^{20}=\left(3^2\right)^{10}=9^{10}\\ Vì:8^{10}< 9^{10}\left(Vì:8< 9\right)\Rightarrow2^{30}< 3^{20}\\ b,9^{10}.27^5=\left(3^2\right)^{10}.\left(3^3\right)^5=3^{20}.3^{15}=3^{35}\\ 243^7=\left(3^5\right)^7=3^{35}\\ Vì:3^{35}=3^{35}\Rightarrow243^7=9^{10}.27^5\)

Bài 5:

100< 5^2x-3 < 59

Đề vầy hả em?

a) 1kg = 10 hg

b) 23hg 7đag = 2370 g

c) 51 yến 73kg = 583 kg

d) 7000kg 10 tạ = 17 tấn

Các câu trên làm như POP POP

còn câu d; 7000 kg 10 tạ = 7000 kg + 10 tạ = 7 tấn + 1 tấn = 8 tấn 

38 - x.12 - x.16 = 40

38 - x.(12+16) = 40

38 - 28.x = 40

28.x = 40 - 38

28.x = 2

x= 2/28

x=1/14

100 - 50:(x-4)=75

50:(x-4)= 100 - 75

50:(x-4)=25

x-4= 50:25

x-4=2

x=2+4

x=6

6 nhaa