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2 tháng 7 2021
Câu trả lời bằng hình

Bài tập Tất cả

2 tháng 7 2021
Mình gửi lại ảnh nhé

Bài tập Tất cả

21 tháng 7 2021

Trả lời:

a, \(A=\frac{x^2-9}{x^2-6x+9}=\frac{\left(x-3\right)\left(x+3\right)}{\left(x-3\right)^2}=\frac{x+3}{x-3}\)

b, \(B=\frac{9x^2-16}{3x^2-4x}=\frac{\left(3x-4\right)\left(3x+4\right)}{x\left(3x-4\right)}=\frac{3x+4}{x}\)

c, \(C=\frac{x^2+4x+4}{2x+4}=\frac{\left(x+2\right)^2}{2\left(x+2\right)}=\frac{x+2}{2}\)

d, \(D=\frac{2x-x^2}{x^2-4}=\frac{x\left(2-x\right)}{\left(x-2\right)\left(x+2\right)}=-\frac{x\left(x-2\right)}{\left(x-2\right)\left(x+2\right)}=-\frac{x}{x+2}\)

e, \(E=\frac{3x^2+6x+12}{x^3-8}=\frac{3\left(x^2+2x+4\right)}{\left(x-2\right)\left(x^2+2x+4\right)}=\frac{3}{x-2}\)

24 tháng 2 2020

d, \(\frac{x+1}{9}+\frac{x+2}{8}=\frac{x+3}{7}+\frac{x+4}{6}\)

\(\Leftrightarrow\frac{x+1}{9}+1+\frac{x+2}{8}+1=\frac{x+3}{7}+1+\frac{x+4}{6}+1\)

\(\Leftrightarrow\frac{x+10}{9}+\frac{x+10}{8}-\frac{x+10}{7}-\frac{x+10}{6}=0\)

\(\Leftrightarrow\left(x+10\right)\left(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\right)=0\)

\(\Leftrightarrow x+10=0\) (Vì \(\frac{1}{9}+\frac{1}{8}-\frac{1}{7}-\frac{1}{6}\) ≠ 0)

\(\Leftrightarrow x=-10\)

Vậy x = -10 là nghiệm của phương trình.

24 tháng 2 2020

Hỏi đáp ToánHỏi đáp Toán

24 tháng 7 2021

\(ĐKXĐ:x\ne2;x\ne-2;x\ne0\)

\(a,P=\left(\frac{-1}{2-x}-\frac{2x}{4-x^2}+\frac{1}{2+x}\right)\left(\frac{2}{x}-1\right)\)

\(P=\left(\frac{-2-x+2-x-2x}{\left(2-x\right)\left(2+x\right)}\right)\left(\frac{2-x}{x}\right)\)

\(P=\frac{-4x}{\left(2-x\right)\left(2+x\right)}\frac{2-x}{x}\)

\(P=\frac{-4}{2+x}\)

\(b,P=\frac{-4}{2+x}=\frac{1}{2}\)

\(2+x=-8\)

\(x=-10\)

\(c,P=-\frac{4}{2+x}\)

\(< =>-4⋮x+2\)

lập bảng ra thì bạn ra đc \(x=\left\{2;-1;-3;-6\right\}\)

24 tháng 7 2021

a)\(P=\left(\frac{1}{x-2}-\frac{2x}{4-x^2}+\frac{1}{2+x}\right)\left(\frac{2}{x}-1\right)\)

\(P=\left(\frac{1}{x-2}+\frac{2x}{\left(x+2\right)\left(x-2\right)}+\frac{1}{2+x}\right).\frac{2-x}{x}\)

\(P=\frac{x+2+2x+x-2}{\left(x-2\right)\left(x+2\right)}.\frac{2-x}{x}\)

\(P=\frac{4x}{\left(x-2\right)\left(x+2\right)}.\frac{2-x}{x}\)

\(P=\frac{-4}{x+2}\)

b) Để P=1/2

\(\Rightarrow-\frac{4}{x+2}=\frac{1}{2}\)

\(\Leftrightarrow-8=x+2\)

\(\Leftrightarrow x=-10\)

c) Để P nhận GT nguyên

\(\Rightarrow\left(x+2\right)\inƯ_{\left(-4\right)}\)

\(\Rightarrow\left(x+2\right)\in\left\{-1;1;-2;2;-4;4\right\}\)

\(\Rightarrow x=\left\{-3;-1;-4;0;-6;2\right\}\)

#H

Làm đc 2 bài đầu chưa, t làm câu cuối cho, hai câu đầu dễ í mà

10 tháng 3 2020

1. \(1+\frac{2x-5}{x-2}-\frac{3x-5}{x-1}=0\)

\(\Rightarrow\frac{\left(x-2\right)\left(x-1\right)}{\left(x-2\right)\left(x-1\right)}+\frac{\left(2x-5\right)\left(x-1\right)}{\left(x-2\right)\left(x-1\right)}-\frac{\left(3x-5\right)\left(x-2\right)}{\left(x-2\right)\left(x-1\right)}=0\)

\(\Rightarrow x^2-x-2x+2+2x^2-2x-5x+5-3x^2+6x+5x-10=0\)

\(\Rightarrow x-3=0\Rightarrow x=3\)

2. \(\frac{x-3}{x-2}-\frac{x-2}{x-4}=3\frac{1}{5}\)

\(\Rightarrow\frac{\left(x-3\right)\left(x-4\right)}{\left(x-2\right)\left(x-4\right)}-\frac{\left(x-2\right)^2}{\left(x-2\right)\left(x-4\right)}-\frac{16}{5}=0\)

\(\Rightarrow x^2-4x-3x+12-x^2+4x-4-16=0\)

\(\Rightarrow-3x-8=0\Rightarrow x=\frac{-8}{3}\)

3. \(\frac{x-2}{2+x}-\frac{3}{x-2}=\frac{2\left(x-11\right)}{x^2-4}\)

\(\Rightarrow\frac{\left(x-2\right)^2}{x^2-4}-\frac{3\left(x+2\right)}{x^2-4}-\frac{2\left(x-11\right)}{x^2-4}=0\)

\(\Rightarrow x^2-4x+4-3x-6-2x+22=0\)

\(\Rightarrow x^2-9x+20=0\)

\(\Rightarrow x^2-4x-5x+20=0\)

\(\Rightarrow x\left(x-4\right)-5\left(x-4\right)=0\)

\(\Rightarrow\left(x-4\right)\left(x-5\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}x-4=0\\x-5=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=4\\x=5\end{matrix}\right.\)

10 tháng 3 2020

cảm ơn pn nhìu

28 tháng 1 2020

\(ĐKXĐ:x\ne\pm5\)

 \(\frac{3}{4\left(x-5\right)}+\frac{15}{50-2x^2}=\frac{-7}{6\left(x+5\right)}\)

\(\Rightarrow\frac{3\left(x+5\right)}{4\left(x-5\right)\left(x+5\right)}+\frac{30}{4\left(25-x^2\right)}=\frac{-7\left(x-5\right)}{6\left(x+5\right)\left(x-5\right)}\)

\(\Rightarrow\frac{3x+15}{4\left(x-5\right)\left(x+5\right)}+\frac{-30}{4\left(x-5\right)\left(x+5\right)}=\frac{-7\left(x-5\right)}{6\left(x+5\right)\left(x-5\right)}\)

\(\Rightarrow\frac{3x+15-30}{4\left(x-5\right)\left(x+5\right)}=\frac{-7\left(x-5\right)}{6\left(x+5\right)\left(x-5\right)}\)

\(\Rightarrow\frac{3x-15}{4\left(x-5\right)\left(x+5\right)}=\frac{-7\left(x-5\right)}{6\left(x+5\right)\left(x-5\right)}\)

\(\Rightarrow\frac{3\left(x-5\right)}{4\left(x-5\right)\left(x+5\right)}=\frac{-7\left(x-5\right)}{6\left(x+5\right)\left(x-5\right)}\)

\(\Rightarrow\frac{3}{4\left(x+5\right)}=\frac{-7}{6\left(x+5\right)}\)

\(\Rightarrow18\left(x+5\right)=-28\left(x+5\right)\)

\(\Rightarrow18\left(x+5\right)+28\left(x+5\right)=0\)

\(\Rightarrow46\left(x+5\right)=0\Leftrightarrow x+5=0\Leftrightarrow x=-5\)(ktm)

Vậy pt vô nghiệm

11 tháng 5 2019

a.(x+2)2-x(x+2)=0

\(\Leftrightarrow\)(x+2)(x-2-x)=0

\(\Leftrightarrow\)(x+2)*2=0

\(\Leftrightarrow\)x+2=0

\(\Leftrightarrow\)x=-2

vay s={-2}

b.\(\frac{2x+7}{3}\)-\(\frac{x-2}{4}\)=2

\(\Leftrightarrow\)\(\frac{4\left(2x+7\right)}{12}\)+\(\frac{-3\left(x-2\right)}{12}\)=\(\frac{24}{12}\)

\(\Leftrightarrow\)8x+28-3x+6=24

\(\Leftrightarrow\)5x=-10

\(\Leftrightarrow\)x=-2

vay s={-2}

c.|x+5|=3x+1

neu x+5\(\ge\)0 thi |x+5|=x+5

\(\Leftrightarrow\)x\(\ge\)-5

ta co phuong trinh

x+5=3x+1

\(\Leftrightarrow\)-2x=-4

\(\Leftrightarrow\)x=2( thoa man dieu kien x\(\ge\)-5)

neu x+5<0 thi |x+5|=5-x

\(\Leftrightarrow\)x<-5

ta co phuong trinh

5-x=3x+1

\(\Leftrightarrow\)-4x=-4

\(\Leftrightarrow\)x=1 (k thoa man dieu kien x<5)

vay s={2}

chuc bn hoc totbanh

11 tháng 5 2019

a, -2

b, -2

c, 2

a) \(\frac{x+3}{x-2}-\frac{2x+3}{x+2}=\frac{2x^2+5x+12}{x^2-4}\)

ĐKXĐ: \(\left\{\begin{matrix}x\ne2\\x\ne-2\end{matrix}\right.\)

\(\Rightarrow\left(x+3\right)\left(x+2\right)-\left(2x+3\right)\left(x-2\right)=2x^2+5x+12\)

\(\Leftrightarrow x^2+2x+3x+6-2x^2+4x-3x+6-2x^2-5x-12=0\)

\(\Leftrightarrow-3x^2+4x=0\)

\(\Leftrightarrow3x^2-4x=0\)

\(\Leftrightarrow x\left(3x-4\right)=0\)

\(\Leftrightarrow\left[\begin{matrix}x=0\\3x-4=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\3x=4\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\left(tmđk\right)\\x=\frac{4}{3}\left(tmđk\right)\end{matrix}\right.\)

Vậy: \(x=0;\frac{4}{3}\)

_Chúc bạn học tốt_

b) Ta có: \(\frac{2x+5}{x-3}+\frac{x-1}{x+3}=\frac{x^2+6x+18}{x^2-9}\)

ĐKXĐ: \(\left\{\begin{matrix}x\ne3\\x\ne-3\end{matrix}\right.\)

\(\Leftrightarrow\frac{\left(2x+5\right)\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}+\frac{\left(x-1\right)\left(x-3\right)}{\left(x+3\right)\left(x-3\right)}=\frac{x^2+6x+18}{\left(x+3\right)\left(x-3\right)}\)

\(\Rightarrow\left(2x+5\right)\left(x+3\right)+\left(x-1\right)\left(x-3\right)=x^2+6x-18\)

\(\Leftrightarrow2x^2+6x+5x+15+x^2-3x-x+3-x^2-6x-18=0\)

\(\Leftrightarrow2x^2+x=0\)

\(\Leftrightarrow x\left(2x+1\right)=0\)

\(\Leftrightarrow\left[\begin{matrix}x=0\\2x+1=0\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\2x=-1\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=0\\x=-\frac{1}{2}\end{matrix}\right.\)

Vậy: \(x=0;-\frac{1}{2}\)

_Chúc bạn học tốt_