(1/2x-3)^100=(1/2x-3)^101
HELP ME PLEASE!!!!!!!!!!!!!!!
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\(\frac{38}{10}:2x=\frac{1}{4}\times\frac{3}{8}\)
\(\frac{38}{10}:2x=\frac{3}{32}\)
\(2x=\frac{38}{10}:\frac{3}{32}\)
\(2x=\frac{38}{10}\times\frac{32}{3}\)
\(2x=\frac{608}{15}\)
\(x=\frac{608}{15}\times\frac{1}{2}\)
\(x=\frac{304}{15}\)
\(|\frac{2x-1}{3}|+\frac{2}{5}=0.75\)
\(\Rightarrow|\frac{2x-1}{3}|=\frac{7}{4}-\frac{2}{5}=\frac{27}{20}\)
\(\Rightarrow\hept{\begin{cases}\frac{2x-1}{3}=\frac{27}{20}\\\frac{2x-1}{3}=-\frac{27}{20}\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}2x-1=\frac{81}{20}\\2x-1=-\frac{81}{20}\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{101}{40}\\x=-\frac{61}{40}\end{cases}}\)
P/s : Không chắc :))
\(\left|2x-\frac{1}{3}\right|+\frac{2}{5}=0.75\)
\(\left|2x-\frac{1}{3}\right|+\frac{2}{5}=\frac{3}{4}\)
\(\Rightarrow\left|2x-\frac{1}{3}\right|=\frac{7}{20}\)
\(\Rightarrow\orbr{\begin{cases}2x-\frac{1}{3}=\frac{7}{20}\\2x-\frac{1}{3}=-\frac{7}{20}\end{cases}}\Rightarrow\orbr{\begin{cases}2x=\frac{41}{60}\\2x=-\frac{1}{60}\end{cases}}\Rightarrow\orbr{\begin{cases}x=\frac{41}{120}\\x=-\frac{1}{120}\end{cases}}\)(Đến đoạn này bạn tính lại hộ mình nhé.mik hay tính sai:3)
Câu a :
\(x^2-2x-3=0\)
\(\Leftrightarrow x^2-x+3x-3=0\)
\(\Leftrightarrow x\left(x-1\right)+3\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0\Rightarrow x=1\\x+3=0\Rightarrow x=-3\end{matrix}\right.\)
Câu b :
\(2x^2+3=-5x\)
\(\Leftrightarrow2x^2+3+5x=0\)
\(\Leftrightarrow2x^2+2x+3x+3=0\)
\(\Leftrightarrow2x\left(x+1\right)+3\left(x+1\right)=0\)
\(\Leftrightarrow\left(x+1\right)\left(2x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x+1=0\Rightarrow x=-1\\2x+3=0\Rightarrow x=-\dfrac{3}{2}\end{matrix}\right.\)
Mấy câu sau khó quá ko bt làm :)
a) Cậu xem lại đề đi
b) \(3x.\left(x-2\right)-5x.\left(1-x\right)-8.\left(x^2-3\right)=4\)\(\Leftrightarrow3x^2-6x-5x+5x^2-8x^2+24-4=0\Leftrightarrow-11x+20=0\Leftrightarrow-11x=-20\Leftrightarrow x=\frac{20}{11}\)
c) \(2x^2+3.\left(x-1\right)\left(x+1\right)=5x\left(x+1\right)\Leftrightarrow2x^2+3\left(x^2-1\right)-5x\left(x+1\right)=0\)
\(\Leftrightarrow2x^2+3x^2-3-5x^2-5x=0\Leftrightarrow-5x=3\Leftrightarrow x=-\frac{3}{5}\)
Trần Anh: Cảm ơn bạn nhiều nhé :)) Phần a đúng là có sai đề pạn ạ mik làm hoài mà cux ko ra hì hì !!~~ Dù sao mik cux cảm ơn pạn nhiều nhiều nhé :3
a)\(-3x\left(x+2\right)^2+\left(x+3\right)\left(x-1\right)\left(x+1\right)-\left(2x-3\right)^2\)
\(=-3x.\left(x^2+2.x.2+2^2\right)+\left(x^2+x+3x-3\right).\left(x+1\right)-\left(2x\right)^2-2.2.x.\left(-3\right)+\left(-3\right)^2\)
\(=-3x.\left(x^2+4x+4\right)+\left(x^2+\left(x+3x\right)-3\right).\left(x+1\right)-4x+12x+9\)
\(=-3x.\left(x^2+4x+4\right)+\left(x^2+4x-3\right)\left(x+1\right)-4x+12x+9\)
\(=-3x^3-12x^2-12x+x^3+4x^2-3x+x^2+4x-3-4x+12x+9\)
\(=\left(-3x^3-x^3\right)+\left(-12x^2+4x^2+x^2\right)+\left(-12x-3x+4x-4x+12x\right)+\left(-3+9\right)\)
\(=-2x^3-7x^2-3x+6\)
b)\(\left(x-3\right)\left(x+3\right)\left(x+2\right)-\left(x-1\right)\left(x^2-3\right)-5x\left(x+4\right)^2-\left(x-5\right)^2\)
\(=\left(x.\left(x+3\right)-3\left(x+3\right)\right)\left(x+2\right)-\left(x.\left(x^2-3\right)-1\left(x^2-3\right)\right)-5x\left(x+4\right)^2-\left(x-5\right)^2\)
\(=\left(x.x+x.3-3.x+\left(-3\right).3\right)\left(x+2\right)-\left(x.x^2+x.\left(-3\right)-1.x^2+\left(-1\right).\left(-3\right)\right)-5x.x+\left(-5x\right).4-x^2-2x5+5^2\)
\(=\left(x^2+3x-3x-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^2+\left(3x-3x\right)-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^2-9\right)\left(x+2\right)-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=x^3+2x^2-9x-15-x^3-3x-x^2+3-5x^2-20x-x^2-10x+25\)
\(=\left(x^3-x^3\right)+\left(2x^2-x^2-5x^2-x^2\right)+\left(-9x-3x-20x-10x\right)+\left(-18+3+25\right)\)
\(=-5x^2-42x+10\)
\(\frac{1}{2}\)\(x-3=0\)\(hay\)\(1\)
\(=>\)\(\frac{1}{2}\)\(x\)\(=3\)\(hay\)\(4\)
\(=>x=6;8\)
mơn :)