Giải Phương trình: 13 - x / x+3 - 6x^2 + 6 / x^4 - 8x^2 - 9 - 3x + 6 / x^2 + 5x + 6 - 2 / x -3 =0
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dkxd:
\(x\ne3;x\ne-3\\ \frac{13-x}{x+3}+\frac{6x^2+6}{x^4_{ }-8x^2-9}-\frac{3x+6}{x^2+5x+6}-\frac{2}{x-3}=0\\ \Leftrightarrow\frac{13-x}{x+3}+\frac{6\left(x^2+1\right)}{\left(x^2+1\right)\left(x^2-9\right)}-\frac{3\left(x+2\right)}{\left(x+2\right)\left(x+3\right)}-\frac{2}{x+3}=0\\ \Leftrightarrow\frac{13-x}{x+3}+\frac{6}{\left(x-3\right)\left(x+3\right)}-\frac{3}{x+3}-\frac{2}{x-3}=0\\ \Leftrightarrow\frac{\left(13-x\right)\left(x-3\right)+6-3\left(x-3\right)-2\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}=0\\ \Leftrightarrow\frac{-x^2+16x-39+6-3x+9-2x-6}{\left(x-3\right)\left(x+3\right)}=0\\ \Leftrightarrow-x^2+11x-30=0\\ \Leftrightarrow-\left(x-5\right)\left(x-6\right)=0\\ \Leftrightarrow\left[\begin{matrix}x=5\left(tmdkxd\right)\\x=6\left(tmdkxd\right)\end{matrix}\right.\)
Vay phuong trinh co tap nghiem la S={5;6}
Mấy cái này chuyển vế đổi dấu là xong í mà :3
1,
16-8x=0
=>16=8x
=>x=16/8=2
2,
7x+14=0
=>7x=-14
=>x=-2
3,
5-2x=0
=>5=2x
=>x=5/2
Mk làm 3 cau làm mẫu thôi
Lúc đăng đừng đăng như v :>
chi ra khỏi ngt nản
từ câu 1 đến câu 8 cs thể làm rất dễ,bn tham khảo bài của bn muwaa r làm những câu cn lại
20) -5-(x + 3) = 2 - 5x ⇔ -5 - x - 3 = 2 -5x ⇔ 4x = 10 ⇔ x = \(\frac{5}{2}\)
Vậy...
\(\frac{13-x}{x+3}+\frac{6x^2+6}{x^4-8x^2-9}-\frac{3x+6}{x^2+5x+6}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{13-x}{x+3}+\frac{6\left(x^2+1\right)}{x^4-8x^2+16-25}-\frac{3\left(x+2\right)}{x^2+2x+3x+6}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{13-x}{x+3}+\frac{6\left(x^2+1\right)}{\left(x^4-8x^2+16\right)-5^2}-\frac{3\left(x+2\right)}{x\left(x+2\right)+3\left(x+2\right)}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{13-x}{x+3}+\frac{6\left(x^2+1\right)}{\left(x^2-4\right)^2-5^2}-\frac{3\left(x+2\right)}{\left(x+2\right)\left(x+3\right)}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{13-x}{x+3}-\frac{3}{x+3}+\frac{6\left(x^2+1\right)}{\left(x^2+1\right)\left(x^2-9\right)}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{10-x}{x+3}+\frac{6}{\left(x-3\right)\left(x+3\right)}-\frac{2}{x-3}=0\)
\(\Leftrightarrow\frac{\left(10-x\right)\left(x-3\right)+6-2\left(x+3\right)}{\left(x-3\right)\left(x+3\right)}=0\)
\(\Leftrightarrow10x-30-x^2+3x+6-2x-6=0\)
\(\Leftrightarrow-x^2+11x-30=0\)
\(\Leftrightarrow-x^2+5x+6x-30=0\)
\(\Leftrightarrow-x\left(x-5\right)+6\left(x-5\right)=0\)
\(\Leftrightarrow\left(x-5\right)\left(-x+6\right)=0\)
\(\Leftrightarrow\left[\begin{matrix}x-5=0\\-x+6=0\end{matrix}\right.\)
\(\Rightarrow\left[\begin{matrix}x=5\\x=6\end{matrix}\right.\)
Vậy x=5 ;x=6
A=\(\frac{13-x}{x+3}+\frac{6x^2+6}{x^4-8x^2-9}-\frac{3x+6}{\left(x+2\right)\left(x+3\right)}-\frac{2}{x-3}=0\)\(\Leftrightarrow\frac{13-x}{x+3}+\frac{6\left(x^2+1\right)}{\left(x-3\right)\left(x+3\right)\left(x^2+1\right)}-\frac{3\left(x+2\right)}{\left(x+2\right)\left(x+3\right)}-\frac{2}{x-3}=0\) ( với \(x^4-8x^2-9=x^4-9x^2+x^2-9=x^2\left(x^2-9\right)+\left(x^2-9\right)=\left(x^2-9\right)\left(x^2+1\right)=\left(x-3\right)\left(x+3\right)\left(x^2+1\right)\)
A= \(\frac{13-x}{x+3}+\frac{6}{\left(x-3\right)\left(x+3\right)}-\frac{3}{x+3}-\frac{2}{x-3}=0\) \(\Leftrightarrow\frac{10-x}{x+3}+\frac{6}{\left(x-3\right)\left(x+3\right)}-\frac{2}{x-3}=0\) \(\Leftrightarrow\left(10x-30\right)\left(x-3\right)+6-2\left(x+3\right)=0\Leftrightarrow-x^2+11x-30=0\) \(\Leftrightarrow\left[\begin{array}{nghiempt}x=6\\x=5\end{array}\right.\)
ĐK: \(x\ne-3,3,-2\)
Ta có: \(\frac{13-x}{x+3}+\frac{6x^2+6}{x^4-8x^2-9}-\frac{3x+6}{x^2+5x+6}-\frac{2}{x-3}=0\)
=>\(\frac{13-x}{x+3}+\frac{6x^2+6}{x^4-9x^2+x^2-9}-\frac{3x+6}{x^2+3x+2x+6}-\frac{2}{x-3}=0\)
=>\(\frac{13-x}{x+3}+\frac{6x^2+6}{x^2.\left(x^2-9\right)+\left(x^2-9\right)}-\frac{3x+6}{x.\left(x+3\right)+2.\left(x+3\right)}-\frac{2}{x-3}=0\)
=>\(\frac{13-x}{x+3}+\frac{6.\left(x^2+1\right)}{\left(x^2+1\right).\left(x^2-9\right)}-\frac{3.\left(x+2\right)}{\left(x+2\right).\left(x+3\right)}-\frac{2}{x-3}=0\)
=>\(\frac{13-x}{x+3}+\frac{6}{x^2-9}-\frac{3}{x+3}-\frac{2}{x-3}=0\)
=>\(\left(\frac{13-x}{x+3}-\frac{3}{x+3}\right)+\left(\frac{6}{x^2-9}-\frac{2}{x-3}\right)=0\)
=>\(\frac{13-x-3}{x+3}+\left[\frac{6}{x^2-9}-\frac{2.\left(x+3\right)}{\left(x-3\right).\left(x+3\right)}\right]=0\)
=>\(\frac{10-x}{x+3}+\left[\frac{6}{x^2-9}-\frac{2x+6}{x^2-9}\right]=0\)
=>\(\frac{10-x}{x+3}+\frac{6-2x-6}{x^2-9}=0\)
=>\(\frac{\left(10-x\right).\left(x-3\right)}{\left(x+3\right).\left(x-3\right)}+\frac{-2x}{x^2-9}=0\)
=>\(\frac{13x-x^2-30}{x^2-9}-\frac{2x}{x^2-9}=0\)
=>\(\frac{13x-x^2-30-2x}{x^2-9}=0\)
=>\(\frac{11x-x^2-30}{x^2-9}=0\)
Vì \(x\ne-3,3=>x^2\ne0\)
=>11x-x2-30=0
=>6x-30-x2+5x=0
=>6.(x-5)-x.(x-5)=0
=>(6-x).(x-5)=0
=>6-x=0=>x=6
hoặc x-5=0=>x=5
Vậy tập nghiệm của phương trình S=6; 5