Question

[Luong the vinh]

câu 1 :tâp nhiêm cua phuong trinh(x+\(\dfrac{2}{3}\))(x-\(\dfrac{1}{2}\))=0 la                                                                       câu 2:trong cac so 1;2;-2va -3thi sao nao la ngiem cua phuongg trinh x+1=2x+3                         câu3:tap nhiem cua phuong trinh \(\dfrac{\left(-x+2\right)\left(2\text{x}+10\right)}{x^{2^{ }}+10\text{x}+25}\)=0la                                                           câu 4 dieu kien xac đinh cua phuong trinh \(\dfrac{x}{x-1}-\dfrac{3}{x-2}=\dfrac{5\text{x}-1}{x^{2^{ }}-3\text{x+2}}\)la                               câu 5:phuong trinh 2y +  m=y-1nhan y = 3  la ngiem khi bang m bang                        câu 10 :ngiem cua phuong trinh x²+\(\dfrac{1}{x-1}=1+\dfrac{1}{1-x}\)la

Answer 1

[Nguyễn Lê Phước Thịnh]

Câu 1:

\(\left(x+\dfrac{2}{3}\right)\cdot\left(x-\dfrac{1}{2}\right)=0\)

=>\(\left[{}\begin{matrix}x+\dfrac{2}{3}=0\\x-\dfrac{1}{2}=0\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}x=-\dfrac{2}{3}\\x=\dfrac{1}{2}\end{matrix}\right.\)

Câu 2:

x+1=2x+3

=>x-2x=3-1

=>-x=2

=>x=-2

=>-2 là nghiệm

Câu 3:

ĐKXĐ: x<>-5

\(\dfrac{\left(-x+2\right)\left(2x+10\right)}{x^2+10x+25}=0\)

=>\(\dfrac{\left(-x+2\right)\cdot2\cdot\left(x+5\right)}{\left(x+5\right)^2}=0\)

=>\(\dfrac{2\left(-x+2\right)}{\left(x+5\right)}=0\)

=>-x+2=0

=>x=2(nhận)

Câu 4:

ĐKXĐ: \(\left\{{}\begin{matrix}x-1\ne0\\x-2\ne0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}x\ne1\\x\ne2\end{matrix}\right.\)

Câu 10: ĐKXĐ: x<>1

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

=>\(x^2-1+\dfrac{1}{x-1}+\dfrac{1}{x-1}=0\)

=>\(\left(x-1\right)\left(x+1\right)+\dfrac{2}{x-1}=0\)

=>\(\dfrac{\left(x^2-1\right)\cdot\left(x-1\right)+2}{x-1}=0\)

=>\(x^3-x^2-x+1+2=0\)

=>\(x^3-x^2-x+3=0\)

=>\(x\simeq-1,36\)