giai bat phuong trinh
\(2\sqrt{3x+4}+3\sqrt{5x+9}\ge x^2+6x+13\)
Những câu hỏi liên quan
giai bpt: \(2\sqrt{3x+4}+3\sqrt{5x+9}\ge x^2+6x+13\)
Giai phuong trinh
1/ sqrt{x^2+4x+5}+sqrt{x^2-6x+13}3
2/ sqrt{3x^2-18x+28}+sqrt{4x^2-24x+45}6x-x^2-5
3/ sqrt{2x^2-4x+27}+sqrt{3x^2-6x+12}4x^2+8x+4
4/ sqrt{x^2+x+7}+sqrt{x^2+x+2}sqrt{3x^2+3x+19}
5/ left(x+2right)left(x+3right)-sqrt{x^2+5x+1}9
6/ left(x+4right)left(x+1right)-3sqrt{x^2+5x+2}6
7/ sqrt{2x^2+3x+5}+sqrt{2x^2-3x+5}3sqrt{x}
Đọc tiếp
Giai phuong trinh
1/ \(\sqrt{x^2+4x+5}+\sqrt{x^2-6x+13}=3\)
2/ \(\sqrt{3x^2-18x+28}+\sqrt{4x^2-24x+45}=6x-x^2-5\)
3/ \(\sqrt{2x^2-4x+27}+\sqrt{3x^2-6x+12}=4x^2+8x+4\)
4/ \(\sqrt{x^2+x+7}+\sqrt{x^2+x+2}=\sqrt{3x^2+3x+19}\)
5/ \(\left(x+2\right)\left(x+3\right)-\sqrt{x^2+5x+1}=9\)
6/ \(\left(x+4\right)\left(x+1\right)-3\sqrt{x^2+5x+2}=6\)
7/ \(\sqrt{2x^2+3x+5}+\sqrt{2x^2-3x+5}=3\sqrt{x}\)
Em xin phép làm bài EZ nhất :)
4,ĐK :\(\forall x\in R\)
Đặt \(x^2+x+2=t\) (\(t\ge\dfrac{7}{4}\))
\(PT\Leftrightarrow\sqrt{t+5}+\sqrt{t}=\sqrt{3t+13}\)
\(\Leftrightarrow2t+5+2\sqrt{t\left(t+5\right)}=3t+13\)
\(\Leftrightarrow t+8=2\sqrt{t^2+5t}\)
\(\Leftrightarrow\left\{{}\begin{matrix}t\ge-8\\\left(t+8\right)^2=4t^2+20t\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}t\ge\dfrac{7}{4}\\3t^2+4t-64=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}t\ge\dfrac{7}{4}\\\left(t-4\right)\left(3t+16\right)=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}t\ge\dfrac{7}{4}\\\left[{}\begin{matrix}t=4\left(tm\right)\\t=-\dfrac{16}{3}\left(l\right)\end{matrix}\right.\end{matrix}\right.\)
\(\Rightarrow x^2+x+2=4\)\(\Leftrightarrow x^2+x-2=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=1\\x=-2\end{matrix}\right.\)
Vậy ....
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giai bat phuong trinh sau: (5x-2/3)-(2x2 - x)/2 >= [x(1-3x)] /3 - (5x)/4
\(\left(5x-\frac{2}{3}\right)-\frac{2x^2-x}{2}\ge\frac{x\left(1-3x\right)}{3}-\frac{5x}{4}\)
<=> \(\frac{60x-8-6\left(2x^2-x\right)}{12}\ge\frac{4x\left(1-3x\right)-15x}{12}\)
<=> \(60x-8-12x^2+6x\ge4x-12x^2-15x\)
<=> \(47x\ge8\)
<=> \(x\ge\frac{8}{47}\)
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Giai phuong trinh: \(\sqrt{3x+x^2+\dfrac{9}{4}}+\sqrt{x^2+3x+1}=0\)
Lời giải:
Với mọi $x$ thuộc ĐKXĐ, ta luôn có:
\(\left\{\begin{matrix} \sqrt{3x+x^2+\frac{9}{4}}\geq 0\\ \sqrt{x^2+3x+1}\geq 0\end{matrix}\right.\)
Do đó, để \(\sqrt{3x+x^2+\frac{9}{4}}+\sqrt{x^2+3x+1}=0\) thì:
\(\left\{\begin{matrix} \sqrt{3x+x^2+\frac{9}{4}}= 0\\ \sqrt{x^2+3x+1}=0\end{matrix}\right.\)
\(\Leftrightarrow \left\{\begin{matrix} x=\frac{-3}{2}\\ x=\frac{3\pm \sqrt{5}}{2}\end{matrix}\right.\) (vô lý)
Do đó pt vô nghiệm.
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Giup em voi a
Giai cac bat phuong trinh sau va bieu dien tap nghiem cua bat phuong trinh tren truc so:
a. 2(3x-1)-2x<2x-1
b. 4x-8≥3(3x-2)+4-2x
c. 3(x-2)(x+2)<3x²+x
d. (x+4)(5x-1)>5x²+16x+2
a: =>6x-2-2x<2x-1
=>4x-2<2x-1
=>2x-1<0
=>x<1/2
b: =>4x-8>=9x-6+4-2x
=>4x-8>=7x-2
=>-3x>=6
=>x<=-2
c: =>3x^2-12<3x^2+x
=>x>-12
d: =>5x^2-x+20x-4>5x^2+16x+2
=>19x-4>16x+2
=>3x>6
=>x>2
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giai phuong trinh
\(\sqrt{x-1}-\sqrt{5x-1}=\sqrt{3x-2}\)
DDK : \(x\ge1\)
\(\sqrt{x-1}-\sqrt{5x-1}=\sqrt{3x-2}\)
\(\Leftrightarrow\sqrt{x-1}=\sqrt{3x-2}+\sqrt{5x-1}\)
\(\Rightarrow x-1=3x-2+5x-2+2\sqrt{\left(3x-2\right)\left(5x-1\right)}\)
\(\Leftrightarrow x-1-3x+2-5x+2=2\sqrt{15x^2-3x-10x+2}\)
\(\Leftrightarrow3-7x=2\sqrt{15x^2-13x+2}\)
\(\Rightarrow9-42x+49x^2=4\left(15x^2-13x+2\right)\)
\(\Leftrightarrow9-42x+49x^2=60x^2-52x+8\)
\(\Leftrightarrow11x^2-10x-1=0\)
\(\Leftrightarrow11x^2-11x+x-1=0\)
\(\Leftrightarrow\left(11x+1\right)\left(x-1\right)=0\)
Giải nốt nha .
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giai phuong trinh\(\sqrt{13-4x^4}-2\sqrt[3]{5x^2-4}=1\)
giai phuong trinh
a) \(\sqrt{3x^2-7x+3}-\sqrt{x^2-2}=\sqrt{3x^2-5x-1}-\sqrt{x^2-3x+4}\)
b) x2 - 25 = y ( y + 6 ) (x; y nguyên)
giai bat phuong trinh \(\sqrt{x+2x^2}\)+\(\sqrt[3]{x+4x^3}\ge\)5-2x-\(\frac{1}{x}\)