\(\dfrac{1-x^2}{x^2+3x}\)
help
1/ lim x-> +∞ \(\dfrac{1}{\sqrt{x^2+x+1}-x}\)
2/ lim x->+∞ \(\dfrac{3x-2\sqrt{x}+\sqrt{x^4-5x}}{2x^2+4x-5}\)
help mình vs ạ. cảm ơn ~~~~
\(\dfrac{2-x}{4}\)=\(\dfrac{3x-1}{-3}\)
Help me
\(\dfrac{2-x}{4}=\dfrac{3x-1}{-3}\\ \Rightarrow-3\left(2-x\right)=4\left(3x-1\right)\\ \Rightarrow3x-6=12x-4\\ \Rightarrow12x-4-3x+6=0\\ \Rightarrow9x+2=0\\ \Rightarrow9x=-2\\ \Rightarrow x=-\dfrac{2}{9}\)
\(\dfrac{2-x}{4}=\dfrac{3x-1}{-3}\)
⇒\(\dfrac{3.\left(2-x\right)}{12}\)=\(\dfrac{4.\left(3x-1\right)}{12}\)
⇒\(6x-3=12x-4\)
⇒1=6x
⇒x=\(\dfrac{1}{6}\)
Chúc bạn học tốt!
\(\dfrac{2-x}{4}=\dfrac{3x-1}{-3}\)
\(\Rightarrow-3\left(2-x\right)=4\left(3x-1\right)\)
\(-6+3x=12x-4\)
\(3x-12x=6-2\)
\(-9x=4\)
\(x=\dfrac{4}{-9}\)
\(\dfrac{x+1}{2x+6}+\dfrac{2x+3}{x^2+3x}\)
MN help mình với
Ta có:2x+6=2(x+3);x2+3x=x(x+3)
➞MTC:2x(x+3)
Ta co:(x+1/2x+6)+(2x+3/x2+3x)={[(x+1)x]+[(2x+3)2]}/2x(x+3)=x2+5x+6/2x(x+3)=(x+2)(x+3)/2x(x+3)=x+2/2x
\(\dfrac{1}{\left(x^2-x\right)}+\dfrac{1}{x^2-3x+2}+\dfrac{1}{x^2-5x+6}+\dfrac{1}{\left(x^2+x\right)}=-1\)
Giúp mình với. help me now
\(\Leftrightarrow\dfrac{1}{x\left(x-1\right)}+\dfrac{1}{\left(x-1\right)\left(x-2\right)}+\dfrac{1}{\left(x-2\right)\left(x-3\right)}+\dfrac{1}{x\left(x+1\right)}=-1\left(đkxđ:x\ne\pm1;0;2;3\right)\)
\(\Leftrightarrow\dfrac{1}{x-1}-\dfrac{1}{x}+\dfrac{1}{x-2}-\dfrac{1}{x-1}+\dfrac{1}{x-3}-\dfrac{1}{x-2}+\dfrac{1}{x}-\dfrac{1}{x+1}=-1\)
\(\Leftrightarrow\dfrac{1}{x-3}-\dfrac{1}{x+1}=-1\)
\(\Leftrightarrow\dfrac{4}{x^2-2x-3}=-1\)
\(\Leftrightarrow x^2-2x-3=-4\)
\(\Leftrightarrow x^2-2x+1=0\)
\(\Leftrightarrow\left(x-1\right)^2=0\)
\(\Leftrightarrow x=1\left(loai\right)\)
Vậy không có giá trị x thỏa mãn
Tính giá trị biểu thức \(A=x^2-3x+1\) khi \(\left|x+\dfrac{1}{3}\right|=\dfrac{2}{3}\)
Help me
Giải:
Ta có:
|x+1/3|=2/3
⇒x+1/3=2/3 hoặc x+1/3=-2/3
x=1/3 hoặc x=-1
+)TH1: (nếu như có ngoặc)
Khi x=1/3:
A=(1/3)2-3.(1/3)+1
A=1/9
Khi x=-1
A=(-1)2-3.(-1)+1
A=5
+)TH2: (nếu x ko có ngoặc)
Khi x=-1
A=-12-3.-1+1
A=3
Trường hợp này chỉ có -1 vì 1/3 2 =1/9 ; còn ko có ngoặc hay có ngoặc còn tùy thuộc vào đề bài và cách suy nghĩ của bạn nhé!
Chúc bạn học tốt!
\(\dfrac{3-3x}{5}\)=\(\dfrac{x-1}{2}\) help em vs mn
Tìm x : \(\dfrac{1}{2}-\left|2-3x\right|=\sqrt{\dfrac{19}{16}}-\sqrt{\left(-0,75\right)^2}\)
HELP ME!
\(\dfrac{1}{2}-\left|2-3x\right|=\sqrt{\dfrac{19}{16}}-\sqrt{\left(-0,75\right)^2}\\ \Rightarrow\dfrac{1}{2}-\left|2-3x\right|=\dfrac{\sqrt{19}}{4}-\dfrac{3}{4}\\ \Rightarrow\left|2-3x\right|=\dfrac{1}{2}-\dfrac{\sqrt{19}-3}{4}\)
\(\Rightarrow\left|2-3x\right|=\dfrac{5-\sqrt{19}}{4}\)
\(TH_1:x\le\dfrac{2}{3}\\ 2-3x=\dfrac{5-\sqrt{19}}{4}\\ \Rightarrow3x=\dfrac{3+\sqrt{19}}{4}\\ \Rightarrow x=\dfrac{3+\sqrt{19}}{12}\left(tm\right)\)
\(TH_2:x>\dfrac{2}{3}\\ 3x-2=\dfrac{5-\sqrt{19}}{4}\\ \Rightarrow3x=\dfrac{13-\sqrt{19}}{4}\\ \Rightarrow x=\dfrac{13-\sqrt{19}}{12}\left(tm\right)\)
Vậy \(x\in\left\{\dfrac{3+\sqrt{19}}{12};\dfrac{13-\sqrt{19}}{12}\right\}\)
\(\dfrac{1}{2}-\left|2-3x\right|=\sqrt[]{\dfrac{19}{16}}-\sqrt[]{\left(-0,75\right)^2}\)
\(\Rightarrow\dfrac{1}{2}-\left|2-3x\right|=\dfrac{\sqrt[]{19}}{4}-0,75\)
\(\Rightarrow\dfrac{1}{2}-\left|2-3x\right|=\dfrac{\sqrt[]{19}}{4}-\dfrac{3}{4}\)
\(\Rightarrow\left|2-3x\right|=\dfrac{1}{2}-\dfrac{\sqrt[]{19}}{4}+\dfrac{3}{4}\)
\(\Rightarrow\left|2-3x\right|=\dfrac{5-\sqrt[]{19}}{4}\)
\(\Rightarrow\left[{}\begin{matrix}2-3x=\dfrac{5-\sqrt[]{19}}{4}\\2-3x=\dfrac{-5+\sqrt[]{19}}{4}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}3x=2-\dfrac{5-\sqrt[]{19}}{4}\\3x=2-\dfrac{\sqrt[]{19}-5}{4}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}3x=\dfrac{3+\sqrt[]{19}}{4}\\3x=\dfrac{13-\sqrt[]{19}}{4}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{3+\sqrt[]{19}}{12}\\x=\dfrac{13-\sqrt[]{19}}{12}\end{matrix}\right.\)
I : Giải các phường trình sau
a) \(\left(3x-2\right)\left(\dfrac{2\left(x+3\right)}{7}-\dfrac{4x-3}{5}\right)=0\)
b) \(\left(x-\dfrac{3}{4}\right)^2+\left(x-\dfrac{3}{4}\right)\left(x-\dfrac{1}{2}\right)=0\)
c) \(\dfrac{12}{9-x^2}+\dfrac{2}{x-3}+\dfrac{3}{x+3}=1\)
d) \(\dfrac{1}{x-1}+\dfrac{2}{x^2+x+1}=\dfrac{3x^2}{x^3-1}\)
help me
\(\dfrac{x^2+xy}{5x^2-5y^2}.\dfrac{3x^3-3y^3}{x^2-xy}\)
help me all bro
=\(^{\dfrac{-x^2-xy}{5\left(x^2-y^2\right)}}\).\(\dfrac{3\left(x^3-y^3\right)}{x^2-xy}\)
=\(\dfrac{-3\left(x-y\right)}{5}\)