\(\frac{x-3}{x+3}-\frac{x+3}{X-3}=\frac{6x^2}{9-X^2}\)
BÀI 5 : CHO
E=\(\frac{x^2+6x+9}{x^3+3x^2-27x+27}\). \(\left(\frac{x^2+6x+9}{x^3+3x^2-27x+27}+\frac{2}{3x}:\left(\frac{1}{x}+\frac{1}{3}\right)^2\right)\)
F=\(\frac{3+x}{3-x}\) .\(\frac{x^2-6x+9}{9x^2}\).\(\left(\frac{3}{3-x}-\frac{9}{27+x^3}.\frac{x^2-3x+9}{3-x}\right)\)
a, RÚT GỌN E VÀ F
A=\(\left(\frac{3-x}{x+3}.\frac{x^2+6x+9}{x^2-9}+\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
rút gọn A
\(A=\left(\frac{3-x}{x+3}.\frac{x^2+6x+9}{x^2-9}+\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
\(A=\left(\frac{3-x}{x+3}.\frac{\left(x+3\right)^2}{\left(x-3\right)\left(x+3\right)}+\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
\(A=\left(\frac{-\left(x-3\right)}{x+3}.\frac{\left(x+3^2\right)}{\left(x-3\right)\left(x+3\right)}+\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
\(A=\left(-1+\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
\(A=\left(\frac{-x-3+x}{x+3}\right):\frac{3x^2}{x+3}\)
\(A=\left(-\frac{3}{x+3}\right).\frac{x+3}{3x^2}\)
\(A=-x^2\)
\(A=\left(\frac{3-x}{x+3}\cdot\frac{x^2+6x+9}{x^2-9}\cdot\frac{x}{x+3}\right):\frac{3x^2}{x+3}\)
\frac{3}{x-3}-\frac{6x}{9-x^2}+\frac{x}{x+3}
tìm điều kiện xác định
rút gọn
tính x=5
ĐK: `x \ne 3; x \ne -3`
`A=3/(x-3)-(6x)/(9-x^2)+x/(x+3)`
`=3/(x-3)+(6x)/(x^2-9)+x/(x+3)`
`=3/(x-3)+(6x)/((x-3)(x+3))+x/(x+3)`
`=(3(x+3)+6x+x(x-3))/((x-3)(x+3))`
`=(3x+9+6x+x^2-3x)/((x+3)(x-3))`
`=(x^2+6x+9)/((x-3)(x+3))`
`=((x+3)^2)/((x-3)(x+3))`
`=(x+3)/(x-3)`
`x=5 => A=(5+3)/(5-3)=4`
ĐKXĐ:\(\left\{{}\begin{matrix}x-3\ne0\\9-x^2\ne0\\x+3\ne0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne3\\x^2\ne9\\x\ne-3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x\ne3\\x\ne-3\end{matrix}\right.\)
\(\dfrac{3}{x-3}-\dfrac{6x}{9-x^2}+\dfrac{x}{x+3}\\ =\dfrac{3\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}-\dfrac{6x}{\left(3-x\right)\left(3+x\right)}+\dfrac{x\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}\\ =\dfrac{3x+9}{\left(x-3\right)\left(x+3\right)}+\dfrac{6x}{\left(x-3\right)\left(x+3\right)}+\dfrac{x^2-3x}{\left(x-3\right)\left(x+3\right)}\\ =\dfrac{3x+9+6x+x^2-3x}{\left(x-3\right)\left(x+3\right)}\\ =\dfrac{x^2+6x+9}{\left(x-3\right)\left(x+3\right)}\\ =\dfrac{\left(x+3\right)^2}{\left(x-3\right)\left(x+3\right)}\\ =\dfrac{x+3}{x-3}\)
Thay x=5 vào \(\dfrac{x+3}{x-3}=\dfrac{5+3}{5-3}=\dfrac{8}{2}=4\)
Thực hiện phép tình:
\(\left[\frac{1}{x^2+6x+9}-\frac{1}{x^2-6x+9}\right]:\left[\frac{1}{x+3}+\frac{1}{x-3}\right]\)
Thực hiện phép tính
a) \(\frac{xy}{x^2-y^2}-\frac{x^2}{y^2-x^2}\)
b) \(\frac{7}{x}-\frac{x}{x+16}+\frac{36}{x^2-6x}\)
c) \(\frac{18}{\left(x-3\right).\left(x^2-9\right)}-\frac{3}{x^3-6x+9}-\frac{x}{x^2-9}\)
Bạn nào biết làm thì giúp mình nha! Thanks nhiều
$\frac{4x+3}{5}$ -$\frac{6x-2}{7}$ =$\frac{5x+4}{3}$ +3
b.
$\frac{x+4}{5}$ -x+4=$\frac{x}{3}$ -$\frac{x-2}{2}$
c.$\frac{5x+2}{6}$ -$\frac{8x-1}{3}$ =$\frac{4x+2}{5}$ -5
d.$\frac{2x+3}{3}$ =$\frac{5-4}{2}$
e. $\frac{5x+3}{12}$ =$\frac{1+2x}{9}$
f.$\frac{7x-1}{6}$ =$\frac{16-x}{5}$
g. $\frac{x-3}{5}$ =6-$\frac{1-2x}{3}$
h. $\frac{3x-2}{6}$ -5=$\frac{3-2(x+7)}{4}$
giúp vs ạ, cần gấp
d: =>4x+6=15x-12
=>4x-15x=-12-6=-18
=>-11x=-18
hay x=18/11
e: =>\(45x+27=12+24x\)
=>21x=-15
hay x=-5/7
f: =>35x-5=96-6x
=>41x=101
hay x=101/41
g: =>3(x-3)=90-5(1-2x)
=>3x-9=90-5+10x
=>3x-9=10x+85
=>-7x=94
hay x=-94/7
Rút gọn: \(\left(\frac{1}{x^2+6x+9}-\frac{1}{x^2-6x+9}\right)\left(\frac{1}{x+3}+\frac{1}{x-3}\right)\)
1/(x^2+6x+9)-1/(x^2-6x+9)=(x-3)/(x-3)(x+3)-(x+3)/(x-3)(x+3)= -6/(x-3)(x+3)
1/(x+3)+1/(x-3)=
sai rồi bấm lộn thôi mà
I am sorry
Rút gọn : \(\frac{3}{x^2+6x+6}+\frac{3}{6x-x^2-9}+\frac{x^2+30x-27}{x^4-18x^2+81}\)
Sửa đề: \(\dfrac{3}{x^2+6x+9}-\dfrac{3}{x^2-6x+9}+\dfrac{x^2+30x-27}{x^4-18x^2+81}\)
\(=\dfrac{3x^2-18x+27-3x^2-18x-27+x^2+30x-27}{\left(x+3\right)^2\cdot\left(x-3\right)^2}\)
\(=\dfrac{x^2-6x-27}{\left(x+3\right)^2\cdot\left(x-3\right)^2}=\dfrac{\left(x-9\right)\left(x+3\right)}{\left(x+3\right)^2\cdot\left(x-3\right)^2}\)
\(=\dfrac{\left(x-9\right)}{\left(x^2-9\right)\left(x-3\right)}\)