\(x^3-5x^2+14x-4=6\sqrt[3]{x^2-x+1}\)
Những câu hỏi liên quan
giải phương trình :
a,\(\sqrt{5x^2+14x+9}-5\sqrt{x+1}=\sqrt{x^2-x-2}\)
b, \(x^2-8x+17=3\sqrt{x^3-7x+6}\)
c, \(x^2+5x+2=4\sqrt{x^3+3x^2+x-1}\)
Phương pháp 6. Biến đổi về dạng \(A^2=B^2\)
a \(x^2+4\sqrt{x+3}=3x+6\)
b \(4x^2+14x+11=4\sqrt{6x+10}\)
c \(4\sqrt{x+1}=x^2-5x+14\)
a) ĐKXĐ : \(x\ge-3\)\(pt\Leftrightarrow x^2-2x+1=x+3-4\sqrt{x+3}+4\Leftrightarrow\left(x-1\right)^2=\left(\sqrt{x+3}-2\right)^2\Leftrightarrow x-1=\sqrt{x+3}-2\Leftrightarrow x+1=\sqrt{x+3}\Leftrightarrow\left(x+1\right)^2=x+3\left(x\ge-1\right)\Leftrightarrow x^2+2x+1=x+3\Leftrightarrow x^2+x-2=0\Leftrightarrow\left[{}\begin{matrix}x=1\left(tmdk\right)\\x=-2\left(kotm\right)\end{matrix}\right.\)
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Bình luận (1)
1,p(x) = 3x^3+5x^2-26x+8
2,p(x)=x^3-7x^2+14x-8
3,p(x)=x^3-x^2-14x+24
4,p(x)=x^4-5x^3+5x^2+5x-6
giải pt :
a,\(3\sqrt{x^2+4x-5}+\sqrt{x-3}=\sqrt{11x^2+25x+2}\)
b,\(\sqrt{5x^2+14x+9}-5\sqrt{x+1}=\sqrt{x^2-x-2}\)
c, \(x^2-8x+17=3\sqrt{x^3-7x+6}\)
30 tháng 7 2021 lúc 20:10
Giair phương trình:1) sqrt[5]{32-x^2}-sqrt[5]{1-x^2}42) sqrt{x}+sqrt[4]{20-x}43) x^3+12sqrt{3x-1}4) sqrt[3]{x-1}+3sqrt[4]{82-x}5) a.left(x+3sqrt{x}+2right)left(x+9sqrt{x}+18right)168xb.sqrt{5x^2+14x+9}-sqrt{x^2-x-20}5sqrt{x+1}
Đọc tiếp
Giair phương trình:
1) \(\sqrt[5]{32-x^2}-\sqrt[5]{1-x^2}=4\)
2) \(\sqrt{x}+\sqrt[4]{20-x}=4\)
3) \(x^3+1=2\sqrt{3x-1}\)
4) \(\sqrt[3]{x-1}+3=\sqrt[4]{82-x}\)
5)
\(a.\left(x+3\sqrt{x}+2\right)\left(x+9\sqrt{x}+18\right)=168x\)
\(b.\sqrt{5x^2+14x+9}-\sqrt{x^2-x-20}=5\sqrt{x+1}\)
a) ĐKXĐ: \(x\ge0\)
Ta có: \(\left(x+3\sqrt{x}+2\right)\left(x+9\sqrt{x}+18\right)=168x\)
\(\Leftrightarrow\left(\sqrt{x}+1\right)\left(\sqrt{x}+2\right)\left(\sqrt{x}+3\right)\left(\sqrt{x}+6\right)=168x\)
\(\Leftrightarrow\left(x+6\right)^2+12\sqrt{x}\left(x+6\right)-133=0\)
\(\Leftrightarrow\left(x+6\right)^2+19\sqrt{x}\left(x+6\right)-7\sqrt{x}\left(x+6\right)-133=0\)
\(\Leftrightarrow\left(x+6\right)\left(x+19\sqrt{x}+6\right)-7\sqrt{x}\left(x+19\sqrt{x}+6\right)=0\)
\(\Leftrightarrow\left(x-7\sqrt{x}+6\right)=0\)
\(\Leftrightarrow\left(\sqrt{x}-1\right)\left(\sqrt{x}-6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=36\end{matrix}\right.\)
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Bình luận (1)
7 tháng 11 2019 lúc 16:04
giải pt
a) \(\sqrt{x+2\sqrt{x-1}}+3\sqrt{x+8-6\sqrt{x-1}}=1-x\)
b) \(\sqrt{x\sqrt{x-1}-2x+2}+\sqrt{\left(x+3\right)\sqrt{x-1}-4x+4}=\sqrt{x-1}\)
c) \(\sqrt{14x+14\sqrt{14x-49}}+\sqrt{14x-14\sqrt{14x-49}}=14\)
d) \(\sqrt{2x-2\sqrt{2x-1}}-2\sqrt{2x+3-4\sqrt{2x-1}}+3\sqrt{2x+8-6\sqrt{2x-1}}=4\)
a/ ĐKXĐ: \(x\ge1\)
Khi \(x\ge1\) ta thấy \(\left\{{}\begin{matrix}VT>0\\VP=1-x\le0\end{matrix}\right.\) nên pt vô nghiệm
b/ \(x\ge1\)
\(\sqrt{\sqrt{x-1}\left(x-2\sqrt{x-1}\right)}+\sqrt{\sqrt{x-1}\left(x+3-4\sqrt{x-1}\right)}=\sqrt{x-1}\)
\(\Leftrightarrow\sqrt{\sqrt{x-1}\left(\sqrt{x-1}-1\right)^2}+\sqrt{\sqrt{x-1}\left(\sqrt{x-1}-2\right)^2}=\sqrt{x-1}\)
Đặt \(\sqrt{x-1}=a\ge0\) ta được:
\(\sqrt{a\left(a-1\right)^2}+\sqrt{a\left(a-2\right)^2}=a\)
\(\Leftrightarrow\left[{}\begin{matrix}a=0\Rightarrow x=1\\\sqrt{\left(a-1\right)^2}+\sqrt{\left(a-2\right)^2}=\sqrt{a}\left(1\right)\end{matrix}\right.\)
\(\Leftrightarrow\left|a-1\right|+\left|a-2\right|=\sqrt{a}\)
- Với \(a\ge2\) ta được: \(2a-3=\sqrt{a}\Leftrightarrow2a-\sqrt{a}-3=0\Rightarrow\left[{}\begin{matrix}\sqrt{a}=-1\left(l\right)\\\sqrt{a}=\frac{3}{2}\end{matrix}\right.\)
\(\Rightarrow a=\frac{9}{4}\Rightarrow\sqrt{x-1}=\frac{9}{4}\Rightarrow...\)
- Với \(0\le a\le1\) ta được:
\(1-a+2-a=\sqrt{a}\Leftrightarrow2a+\sqrt{a}-3=0\Rightarrow\left[{}\begin{matrix}a=1\\a=-\frac{3}{2}\left(l\right)\end{matrix}\right.\)
\(\Rightarrow\sqrt{x-1}=1\Rightarrow...\)
- Với \(1< a< 2\Rightarrow a-1+2-a=\sqrt{a}\Leftrightarrow a=1\left(l\right)\)
c/ ĐKXĐ: \(x\ge\frac{49}{14}\)
\(\Leftrightarrow\sqrt{14x-49+14\sqrt{14x-49}+49}+\sqrt{14x-49-14\sqrt{14x-49}+49}=14\)
\(\Leftrightarrow\sqrt{\left(\sqrt{14x-49}+7\right)^2}+\sqrt{\left(\sqrt{14x-49}-7\right)^2}=14\)
\(\Leftrightarrow\left|\sqrt{14x-49}+7\right|+\left|7-\sqrt{14x-49}\right|=14\)
Mà \(VT\ge\left|\sqrt{14x-49}+7+7-\sqrt{14x-49}\right|=14\)
Nên dấu "=" xảy ra khi và chỉ khi:
\(7-\sqrt{14x-49}\ge0\)
\(\Leftrightarrow14x-49\le49\Leftrightarrow x\le7\)
Vậy nghiệm của pt là \(\frac{49}{14}\le x\le7\)
d/ ĐKXĐ: \(x\ge\frac{1}{2}\)
\(\Leftrightarrow\sqrt{\left(\sqrt{2x-1}-1\right)^2}-2\sqrt{\left(\sqrt{2x-1}-2\right)^2}+3\sqrt{\left(\sqrt{2x-1}-3\right)^2}=4\)
\(\Leftrightarrow\left|\sqrt{2x-1}-1\right|-2\left|\sqrt{2x-1}-2\right|+3\left|\sqrt{2x-1}-3\right|=4\)
TH1: \(\sqrt{2x-1}\ge3\Rightarrow x\ge5\)
\(\sqrt{2x-1}-1-2\sqrt{2x-1}+4+3\sqrt{2x-1}-9=4\)
\(\Leftrightarrow\sqrt{2x-1}=5\)
\(\Leftrightarrow x=13\)
TH2: \(2\le\sqrt{2x-1}< 3\Rightarrow\frac{5}{2}\le x< 5\)
\(\sqrt{2x-1}-1-2\sqrt{2x-1}+4+3\left(3-\sqrt{2x-1}\right)=4\)
\(\Leftrightarrow\sqrt{2x-1}=2\Rightarrow x=\frac{5}{2}\)
TH3: \(1\le\sqrt{2x-1}< 2\Rightarrow1\le x< \frac{5}{2}\)
\(\sqrt{2x-1}-1-2\left(2-\sqrt{2x-1}\right)+3\left(3-\sqrt{2x-1}\right)=4\)
\(\Leftrightarrow4=4\) (luôn đúng)
TH4: \(\frac{1}{2}\le x< 1\)
\(1-\sqrt{2x-1}-2\left(2-\sqrt{2x-1}\right)+3\left(3-\sqrt{2x-1}\right)=4\)
\(\Leftrightarrow\sqrt{2x-1}=1\Rightarrow x=1\left(l\right)\)
Vậy nghiệm của pt là: \(\left[{}\begin{matrix}1\le x\le\frac{5}{2}\\x=13\end{matrix}\right.\)
a.\(\sqrt{5x^2+14x+9}=5\sqrt{x+1}+\sqrt{x^2-8x-20}\)
b.\(\left(x+1\right)\left(x-3\right)+3\sqrt{x^2-x-3}=4\)
c. \(\sqrt{4x^2+x-1}=x+1\)
cứu với mọi ng ơi ☘ 
27 tháng 10 2019 lúc 12:34
giải pt
a) \(\sqrt[3]{x+6}+\sqrt{x-1}=x^2-1\)
b) \(\sqrt[3]{x-9}+2x^2+3x=\sqrt{5x-1}+1\)
c) \(\sqrt{3x+1}-\sqrt{6-x}+3x^2-14x-8=0\)
d) \(\sqrt{x+1}-2\sqrt{4-x}=\frac{5\left(x-3\right)}{\sqrt{2x^2+18}}\)
e) \(x^3+5x^2+6x=\left(x+2\right)\left(\sqrt{2x+2}+\sqrt{5-x}\right)\)
Giải phương trình:
1, \(4\left(2x^2+1\right)+3\left(x^2-2x\right)\sqrt{2x-1}=2\left(x^3+5x\right)\)
2, \(\sqrt{5x^2+4x}-\sqrt{x^2-3x-18}=5\sqrt{x}\)
3, \(\sqrt{5x^2-14x+9}-\sqrt{x^2-x-20}=5\sqrt{x+1}\)