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31 tháng 7 2019

1) \(A=\left|-3,75\right|-\frac{31}{2}+\frac{1}{4}\)

\(A=\frac{15}{4}-\frac{31}{2}+\frac{1}{4}\)

\(A=\left(-\frac{47}{4}\right)+\frac{1}{4}\)

\(A=-\frac{23}{2}.\)

2) \(A=\frac{3}{2}-\left(-3\right)-\left(2,5-3\right)-\left[1,5+\left(-2,5\right)\right]\)

\(A=\frac{3}{2}-\left(-3\right)-\left(-\frac{1}{2}\right)-\left(-1\right)\)

\(A=\frac{9}{2}-\left(-\frac{1}{2}\right)-\left(-1\right)\)

\(A=5-\left(-1\right)\)

\(A=6.\)

Chúc bạn học tốt!

1) \(A=\left|-3.75\right|-\frac{31}{2}+\frac{1}{4}\)

\(\Leftrightarrow A=3.75-\frac{62}{4}+\frac{1}{4}\)

\(\Leftrightarrow A=\frac{15}{4}-\frac{62}{4}+\frac{1}{4}\)

\(\Leftrightarrow A=\frac{15-62+1}{4}\)

\(\Leftrightarrow A=-\frac{46}{4}=-\frac{23}{2}\)

Vậy : \(A=-\frac{23}{2}\)

2) \(A=\frac{3}{2}-\left(-3\right)-\left(2,5-3\right)-\left[1,5+\left(-2,5\right)\right]\)

\(\Leftrightarrow A=\frac{3}{2}+3-\left(-0,5\right)-\left(-1\right)\)

\(\Leftrightarrow A=1,5+3+0,5+1\)

\(\Leftrightarrow A=6\)

Vậy : \(A=6\)

19 tháng 9 2023

`(2/3-0,25+2)-(2-5/2+1/4)-(2,5-1/3)`

`= 2/3 -1/4 +2-2+ 5/2 -1/4 -5/2 +1/3`

`= (2/3 +1/3) +(-1/4 -1/4) + (2-2) + (5/2-5/2)`

`= 3/3 + (-1/2) + 0 + 0`

`= 1 +(-1/2)`

`= 1/2`

DT
19 tháng 9 2023

\(\left(\dfrac{2}{3}-0,25+2\right)-\left(2-\dfrac{5}{2}+\dfrac{1}{4}\right)-\left(2,5-\dfrac{1}{3}\right)\\ =\dfrac{2}{3}-0,25+2-2+\dfrac{5}{2}-\dfrac{1}{4}-2,5+\dfrac{1}{3}\\ =\left(\dfrac{2}{3}+\dfrac{1}{3}\right)+\left(\dfrac{5}{2}-2,5\right)+\left(2-2\right)+\left(-\dfrac{1}{4}-0,25\right)\\ =\dfrac{3}{3}+\left(2,5-2,5\right)+0+\left(-\dfrac{1}{4}-\dfrac{1}{4}\right)\\ =1+0+0+\left(-\dfrac{1}{2}\right)=\dfrac{1}{2}\)

15 tháng 10 2017

\(\dfrac{15}{4}-2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=3\)

\(\Rightarrow2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=\dfrac{15}{4}-3\)

\(\Rightarrow2,5:\left|\dfrac{3}{4}.x+\dfrac{1}{2}\right|=\dfrac{3}{4}\)

\(\Rightarrow\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=2,5:\dfrac{3}{4}\)

\(\Rightarrow\left|\dfrac{3}{4}x+\dfrac{1}{2}\right|=\dfrac{10}{3}\)

\(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{4}x+\dfrac{1}{2}=\dfrac{10}{3}\\\dfrac{3}{4}x+\dfrac{1}{2}=-\dfrac{10}{3}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}\dfrac{3}{4}x=\dfrac{17}{6}\\\dfrac{3}{4}x=\dfrac{-23}{6}\end{matrix}\right.\) \(\Rightarrow\left[{}\begin{matrix}x=\dfrac{34}{9}\\x=\dfrac{-46}{9}\end{matrix}\right.\)

Vậy............

20 tháng 7 2019

a,

-2,5% - { 1- ( \(\frac{2}{3}\)\(^2\)} + ( 1 - \(\frac{4}{9}\))

= -250 - { 1 - \(\frac{4}{9}\)} + \(\frac{5}{9}\)

= -250 - \(\frac{5}{9}\)\(\frac{5}{9}\)

= -250

a: \(=\left(1.25\right)^{16}\cdot8^{16}\cdot8=8\cdot10^{16}\)

b: \(=\left(\dfrac{5}{2}\right)^{13}\cdot4^{13}\cdot4^2=10^{13}\cdot4^2\)

c: \(=\left(0.25\right)^4\cdot8^4\cdot8^2=2^4\cdot8^2=64\cdot16=1024\)

d: \(=\left(\dfrac{1}{2}\right)^{15}\cdot2^{18}=2^3=8\)

e: \(=\left(\dfrac{1}{3}\cdot6\right)^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=2^7\cdot\left(\dfrac{1}{2}\right)^7\cdot\dfrac{1}{2}=\dfrac{1}{2}\)

3 tháng 7 2019

muốn làm ngừi iu a ko 

28 tháng 9 2023

a) \(\left(x-2,5\right)^2=9\)

\(\Leftrightarrow\left[{}\begin{matrix}x-2,5=3\\x-2,5=-3\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=5,5\\x=-0,5\end{matrix}\right.\)

b) \(\left(1-x\right)^3=-8=\left(-2\right)^3\)

\(1-x=-2\)

\(x=3\)

c) \(2^4-x=16\)

\(16-x=16\)

\(x=0\)

28 tháng 9 2023

\(a,\left(x-2,5\right)^2=9\)

\(+,TH1:x-2,5=3\)

\(\Rightarrow x=3+2,5\\\Rightarrow x=5,5\)

\(+,TH2:x-2,5=-3\)

\(\Rightarrow x=-3+2,5\\\Rightarrow x=-0,5\)

\(b,(1-x)^3=-8\)

\(\Rightarrow\left(1-x\right)^3=\left(-2\right)^3\)

\(\Rightarrow1-x=-2\)

\(\Rightarrow x=1-\left(-2\right)\)

\(\Rightarrow x=3\)

\(c,2^4-x=16\)

\(\Rightarrow16-x=16\)

\(\Rightarrow x=0\)

#\(Toru\)