đặt 6x+7=a
suy ra (a-1)(a+1)a2=72
(a2-1)a2=72
a4-a2+1/4=289/4
(a2-1/2)=289/4
hoặc a2-1/2=17/2
a2-1/2=-17/2
suy ra hoặc a2=9
a2=-8(loại vì a2>=0>-8 với mọi a )
suy ra a=3
a=-3
hay 6x+7=3 suy ra x=-2/3
6x+7=-3 suy ra x=-5/3
vậy S={-2/3,-5/3}
Các câu hỏi tương tự
gpt: \(\left(6x+7\right)^2\left(x+1\right)\left(3x+4\right)=6\)
Rút gọn biểu thức:
a) \(\left(6x+1\right)^2+\left(6x-1\right)^2-2\left(1+6x\right)\left(6x-1\right)\)
b) \(3\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\left(2^{16}+1\right)\)
b) left(3x+2right)left(2x+9right)-left(x+2right)left(6x+1right)left(x+1right)-left(x-6right)Leftrightarrowleft(3x+2right)2x+left(3x+2right)9-x.left(6x+1right)-2.left(6x+1right)x+1-x+6Leftrightarrow6x^2+4x+27x+18-6x^2-x-12x-27Leftrightarrow18x+167Leftrightarrow18x-9Leftrightarrow xfrac{-1}{2}Vậy ...
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b) \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
\(\Leftrightarrow\left(3x+2\right)2x+\left(3x+2\right)9-x.\left(6x+1\right)-2.\left(6x+1\right)=x+1-x+6\)
\(\Leftrightarrow6x^2+4x+27x+18-6x^2-x-12x-2=7\)
\(\Leftrightarrow18x+16=7\)
\(\Leftrightarrow18x=-9\)
\(\Leftrightarrow x=\frac{-1}{2}\)
Vậy ...
1) \(\left(3-x^2\right)+6-2x=0\)
2) \(5\left(2x-1\right)+7=4\left(2-x\right)+2\)
3) \(x^2-6x+4\left(x-6\right)=0\)
4) \(\left(x+1\right)\left(2x-3\right)=x\left(x+1\right)\)
Giải các phương trình sau:a) left(x^2+4x+8right)^2+3xleft(x^2+4x+8right)+2x^20b)left(6x+7right)^2left(3x+4right)left(x+1right)6c) left(x-2right)^4+left(x-6right)^482d) 2x^4-5x^3+6x^2-5x+20e) 2x^4+x^3-6x^2+x+20f) x^4+2x^3+4x^2+2x+10đố ai giải được hết!!
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Giải các phương trình sau:
a) \(\left(x^2+4x+8\right)^2+3x\left(x^2+4x+8\right)+2x^2=0\)
b)\(\left(6x+7\right)^2\left(3x+4\right)\left(x+1\right)=6\)
c) \(\left(x-2\right)^4+\left(x-6\right)^4=82\)
d) \(2x^4-5x^3+6x^2-5x+2=0\)
e) \(2x^4+x^3-6x^2+x+2=0\)
f) \(x^4+2x^3+4x^2+2x+1=0\)
đố ai giải được hết!!
Giải phương trình:
\(\frac{\left(6x^4+4x^3-12x^2+9\right)\left(2x^3+7\right)-3\left(4x^3+5\right)\sqrt{6x^4+4x^3-12x^2+9}}{\sqrt{\left(6x^4+4x^3-12x^2+9\right)^3}-18x^3-9}=1\)
=))
giảo các pt sau:
\(\left(6x+7\right)^2\left(3x+4\right)\left(x+1\right)=6\)
\(2x^3\left(2x-3\right)-x^2\left(4x^2-6x+2\right)=0\)0
\(6x^2-\left(2x+5\right).\left(3x-2\right)=7\)\(\)
BÀI 6 tìm x1,2xleft(x-5right)-left(3x+2x^2right)0 2,xleft(5-2xright)+2xleft(x-1right)133,2x^3left(2x-3right)-x^2left(4x^2-6x+2right)0 4,5xleft(x-1right)-left(x+2right)left(5x-7right)65,6x^2-left(2x-3right)left(3x+2right)1 6,2xleft(1-xright)+59-2x^2
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BÀI 6 tìm x
1,\(2x\left(x-5\right)-\left(3x+2x^2\right)=0\) 2,\(x\left(5-2x\right)+2x\left(x-1\right)=13\)
3,\(2x^3\left(2x-3\right)-x^2\left(4x^2-6x+2\right)=0\) 4,\(5x\left(x-1\right)-\left(x+2\right)\left(5x-7\right)=6\)
5,\(6x^2-\left(2x-3\right)\left(3x+2\right)=1\) 6,\(2x\left(1-x\right)+5=9-2x^2\)