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22 tháng 12 2024

\(61-\left(x-2\right)\cdot3=-20\)

\(\left(x-2\right)\cdot3=61-\left(-20\right)\)

\(\left(x-2\right)\cdot3=61+20\)

\(\left(x-2\right)\cdot3=81\)

\(x-2=81\div3\)

\(x-2=27\)

\(x=27+2\)

\(x=29\)

Vậy \(x=29\)

22 tháng 12 2024

(x-2).3=61-(-20)=61+20=81

x-2=81:3=27

x=27+2=29

Vậy x=29

20 tháng 3 2022

\(3,2x-\left(\dfrac{4}{5}+\dfrac{2}{3}\right):3\dfrac{2}{3}=\dfrac{7}{20}\\ \Rightarrow\dfrac{16}{5}x-\dfrac{22}{15}:\dfrac{11}{3}=\dfrac{7}{20}\\ \Rightarrow\dfrac{16}{5}x-\dfrac{2}{5}=\dfrac{7}{20}\\ \Rightarrow\dfrac{16}{5}x=\dfrac{3}{4}\\ \Rightarrow x=\dfrac{15}{64}\)

\(\left(4\dfrac{1}{2}-2x\right).1\dfrac{4}{61}=6\dfrac{1}{2}\\ \Rightarrow\left(\dfrac{9}{2}-2x\right).\dfrac{65}{61}=\dfrac{13}{2}\\ \Rightarrow\dfrac{9}{2}-2x=\dfrac{61}{10}\\ \Rightarrow2x= -\dfrac{8}{5}\\ \Rightarrow x=-\dfrac{4}{5}\)

25 tháng 3 2020

\(\text{1,(-14)+(2x–4^2)=/-10/×/5/}\)

\(-14-16+2x=10.5\)

\(-30+2x=50\)

\(2x=50--30\)

\(2x=80\)

\(x=80:2\)

\(x=40\)

\(\text{2,(-100)–/x+20/=-150}\)

\(|x+20|=-100--150\)

\(|x+20|=50\)

\(\Rightarrow\orbr{\begin{cases}x+20=50\\x+20=-50\end{cases}\Leftrightarrow\orbr{\begin{cases}x=30\\x=-70\end{cases}}}\)

\(\Rightarrow x\in\left\{-70;30\right\}\)

\(\text{3)3x+16=4x–61}\)

\(3x-4x=-61-16\)

\(-x=-77\)

\(\Rightarrow x=77\)

\(\text{4,2(x–5)–3(x+6)=0}\)

\(2x-10-3x-18=0\)

\(2x-3x=0+18+10\)

\(-x=28\)

\(x=-28\)

chúc bạn học tốt

28 tháng 1 2018

Tính giá trị của biểu thức:

a)  324 – 20 + 61 = 356

b) 21 x 3 : 9  = 7

c)  201 + 39 : 3  = 214

d) 123 x (42 - 38) = 528

18 tháng 11 2023

a: ĐKXĐ: \(x\notin\left\{4;-4\right\}\)

\(\dfrac{7}{4x+16}=\dfrac{7}{4\left(x+4\right)}=\dfrac{7\left(x-4\right)}{4\left(x+4\right)\left(x-4\right)}\)

\(\dfrac{11}{x^2-16}=\dfrac{11\cdot4}{4\left(x^2-16\right)}=\dfrac{44}{4\left(x-4\right)\left(x+4\right)}\)

b: \(\dfrac{6}{x\left(x+3\right)^2};\dfrac{x-3}{2x\left(x+3\right)^2}\)

ĐKXĐ: \(x\notin\left\{0;-3\right\}\)

\(\dfrac{6}{x\left(x+3\right)^2}=\dfrac{6\cdot2}{2x\left(x+3\right)^2}=\dfrac{12}{2x\left(x+3\right)^2}\)

\(\dfrac{x-3}{2x\left(x+3\right)^2}=\dfrac{x-3}{2x\left(x+3\right)^2}\)

c: \(\dfrac{-6}{1-x};\dfrac{3x}{x^2+x+1};\dfrac{x^2-3x+5}{x^3-1}\)

ĐKXĐ: \(x\ne1\)

\(-\dfrac{6}{1-x}=\dfrac{6}{x-1}=\dfrac{6\left(x^2+x+1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\dfrac{6x^2+6x+6}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(\dfrac{3x}{x^2+x+1}=\dfrac{3x\left(x-1\right)}{\left(x-1\right)\left(x^2+x+1\right)}=\dfrac{3x^2-3x}{\left(x-1\right)\left(x^2+x+1\right)}\)

\(\dfrac{x^2-3x+5}{x^3-1}=\dfrac{x^2-3x+5}{\left(x-1\right)\left(x^2+x+1\right)}\)

d: \(\dfrac{17}{5x};\dfrac{24}{x-2y};\dfrac{x-y}{8y^2-2x^2}\)

ĐKXĐ: \(x\ne0;x\ne\pm2y\)

\(\dfrac{17}{5x}=\dfrac{17\cdot2\left(x-2y\right)\left(x+2y\right)}{5x\cdot2\cdot\left(x-2y\right)\left(x+2y\right)}=\dfrac{34\left(x^2-4y^2\right)}{10x\left(x-2y\right)\left(x+2y\right)}\)

\(\dfrac{24}{x-2y}=\dfrac{24\cdot10x\left(x+2y\right)}{10x\left(x-2y\right)\left(x+2y\right)}=\dfrac{240x\left(x+2y\right)}{10x\left(x-2y\right)\left(x+2y\right)}\)

\(\dfrac{x-y}{8y^2-2x^2}=\dfrac{-\left(x-y\right)}{2x^2-8y^2}=\dfrac{-\left(x-y\right)}{2\left(x-2y\right)\left(x+2y\right)}\)
\(=\dfrac{-5x\left(x-y\right)}{10x\left(x-2y\right)\left(x+2y\right)}=\dfrac{-5x^2+5xy}{10x\left(x-2y\right)\left(x+2y\right)}\)

29 tháng 4 2023

a) 24 × y : 20 = 480

24 × y = 480 × 20

24 × y = 9600

y = 9600 : 24

y = 400

b) 12862 : y - 296 = 61

12852 : y = 61 + 296

12852 : y = 357

y = 12852 : 357

y = 36