bài 1
1) sprt[6/(3-x)] + sprt[8/(2-x)] = 6
2) sprt[42/(5-x)] + sprt[60/(7-x)] =6
3) x4.\(\sqrt{x+3}\)=2x4+2019-2019x
Những câu hỏi liên quan
A = \sprt{6+2 \sprt{2}. \sprt{3 + \sprt{4+2 \sprt{3}}}
rút gọn biểu thức
giải phương trình #sprt(3x+1) + #sqrt(2-x) = 3
Tìm GTNN,GTLN;
1/[1+\(\sprt {1-x^2}\)
Cho a,b>0 và a3+b3=1.Tìm giá trị lớn nhất của A= sprt{a} + sprt{b}
\(1=\left(a+b\right)\left[\left(a+b\right)^2-3ab\right]\ge\left(a+b\right)\left[\left(a+b\right)^2-\frac{3}{4}\left(a+b\right)^2\right]=\frac{\left(a+b\right)^3}{4}\)
\(\Rightarrow\left(a+b\right)^3\le4\Rightarrow a+b\le\sqrt[3]{4}\)
\(A=\sqrt{a}+\sqrt{b}\le\sqrt{2\left(a+b\right)}\le\sqrt{2\sqrt[3]{4}}\)
\("="\Leftrightarrow a=b=\frac{1}{\sqrt[3]{2}}\)
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Áp dụng phép khai phương một tích
a) \(sqrt{17×51×7\}
b) \(sprt{2,5×12, 5×20\}
a: \(=\sqrt{17^2\cdot21}=17\sqrt{21}\)
b: \(=\sqrt{2.5\cdot2.5\cdot5\cdot20}=2.5\cdot10=25\)
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1. Quebec wanted some from of ..........from the rest of Canada.(separate)
2.The list of their achievements is pretty .......... . (impress)
3. She felt alone and .............(friend)
4. Island is one of the great world.............(religious)
5. We need to get more young people ........... in the sprt (interest)
1. Quebec wanted some from of .....separation.....from the rest of Canada.(separate)
2.The list of their achievements is pretty ....impressive...... . (impress)
3. She felt alone and .....friendless........(friend)
4. Island is one of the great world.....religions........(religious)
5. We need to get more young people ....interested....... in the sprt (interest)
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Hãy chuyển các biểu thức viết trong ngôn ngữ Pascal thành ngôn ngữ Toán học:
a. )spr(b*b + c*c)
b.) (Pi*R1*R1-Pi*R2*R2)/4
c.) sprt(p*(p-a)*(p-b)*(p-c)
a) (a2+c2)2
b) \(\dfrac{PI.R1^2-PI.R2^2}{4}\)
c)\(\sqrt{p.\left(p-a\right).\left(p-b\right)\left(p-c\right)}\)
chúc bạn học tốt!!
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Bài 1 : Tính bằng hai cách
a) ( 6/11 + 5/11 ) x 3/7 =
b) 3/5 x 7/9 - 3/5 x 2/9 =
c) ( 6/7 - 4/7 ) : 2/5 =
d) 8/15 : 2/11 + 7/15 : 2/11 =
Bài 2 : Tính
a) 2 x 3 x4/3 x 4 x 5 =
b) 2/3 x 3/4 x 4/5 : 1/5 =
c) 1 x 2 x 3 x 4 / 5 x 6 x 7 x8 =
d) 2/5 x 3/4 x 5/6 : 3/4 =
a,Cách 1: (6/11 + 5/11 ) x 3/7 Cách 2 :(6/11 + 5/11) x 3/7
= 1 x 3/7 =6/11 x 3/7 + 5/11 x 3/7
= 3/7 = 18/77 + 15/77
= 3/7
b, Cách 1:3/5 x 7/9 - 3/5 x 2/9 Cách 2 :3/5 x 7/9 - 3/5 x 2/9
= 7/15 - 2/15 = 3/5 x (7/9 - 2/9 )
= 1/3 = 3/5 x 5/9
= 1/3
c, Cách 1:(6/7 - 4/7) : 2/5 Cách 2: ( 6/7- 4/7 ) : 2/5
= 2/7 : 2/5 = 6/7 : 2/5 - 4/7 : 2/5
= 5/7 = 15/7 - 10/7
= 5/7
d,Cách 1:8/15 : 2/11 + 7/15 : 2/11 Cách 2:8/15 : 2/11 +7/15 : 2/11
= 88/30 + 77/30 =(8/15+7/15) :2/11
= 11/2 = 1 : 2/11
= 11/2
Bài 2 cậu tự làm nhé !
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\(2a.160\)
\(b.2\)
\(c.\frac{8064}{5}\)
\(d.\frac{1}{3}\)
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A) ( 2/5× 1/2)×3/8 =?
B)7/9 ×3/5 + 4/9 ÷3/5=?
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6 tháng 8 2021 lúc 19:56
Giải phương trình:1. sqrt{dfrac{42}{5-x}}+sqrt{dfrac{60}{7-x}}62. sqrt{x^2-3x+2}+sqrt{x+3}sqrt{x-2}+sqrt{x^2+2x-3}3. x^2+x+12sqrt{x+1}364. sqrt{x+2}-sqrt{x-6}25. sqrt[3]{x-1}-sqrt[3]{x-3}sqrt[3]{2}6. 5sqrt{1+x^3}2left(x^2+2right)6. left(sqrt{x+5}-sqrt{x+2}right)left(1+sqrt{x^2+7x+10}right)3
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Giải phương trình:
1. \(\sqrt{\dfrac{42}{5-x}}+\sqrt{\dfrac{60}{7-x}}=6\)
2. \(\sqrt{x^2-3x+2}+\sqrt{x+3}=\sqrt{x-2}+\sqrt{x^2+2x-3}\)
3. \(x^2+x+12\sqrt{x+1}=36\)
4. \(\sqrt{x+2}-\sqrt{x-6}=2\)
5. \(\sqrt[3]{x-1}-\sqrt[3]{x-3}=\sqrt[3]{2}\)
6. \(5\sqrt{1+x^3}=2\left(x^2+2\right)\)
6. \(\left(\sqrt{x+5}-\sqrt{x+2}\right)\left(1+\sqrt{x^2+7x+10}\right)=3\)
1.
ĐKXĐ: \(x< 5\)
\(\Leftrightarrow\sqrt{\dfrac{42}{5-x}}-3+\sqrt{\dfrac{60}{7-x}}-3=0\)
\(\Leftrightarrow\dfrac{\dfrac{42}{5-x}-9}{\sqrt{\dfrac{42}{5-x}}+3}+\dfrac{\dfrac{60}{7-x}-9}{\sqrt{\dfrac{60}{7-x}}+3}=0\)
\(\Leftrightarrow\dfrac{9x-3}{\left(5-x\right)\left(\sqrt{\dfrac{42}{5-x}}+3\right)}+\dfrac{9x-3}{\left(7-x\right)\left(\sqrt{\dfrac{60}{7-x}}+3\right)}=0\)
\(\Leftrightarrow\left(9x-3\right)\left(\dfrac{1}{\left(5-x\right)\left(\sqrt{\dfrac{42}{5-x}}+3\right)}+\dfrac{1}{\left(7-x\right)\left(\sqrt{\dfrac{60}{7-x}}+3\right)}\right)=0\)
\(\Leftrightarrow x=\dfrac{1}{3}\)
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b.
ĐKXĐ: \(x\ge2\)
\(\sqrt{\left(x-2\right)\left(x-1\right)}+\sqrt{x+3}=\sqrt{x-2}+\sqrt{\left(x-1\right)\left(x+3\right)}\)
\(\Leftrightarrow\sqrt{\left(x-2\right)\left(x-1\right)}-\sqrt{x-2}+\sqrt{x+3}-\sqrt{\left(x-1\right)\left(x+3\right)}=0\)
\(\Leftrightarrow\sqrt{x-2}\left(\sqrt{x-1}-1\right)-\sqrt{x+3}\left(\sqrt{x-1}-1\right)=0\)
\(\Leftrightarrow\left(\sqrt{x-1}-1\right)\left(\sqrt{x-2}-\sqrt{x+3}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\sqrt{x-1}-1=0\\\sqrt{x-2}-\sqrt{x+3}=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=1\\x-2=x+3\left(vn\right)\end{matrix}\right.\)
\(\Rightarrow x=2\)
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3.
ĐKXĐ: \(x\ge-1\)
\(x^2+x-12+12\left(\sqrt{x+1}-2\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+4\right)+\dfrac{12\left(x-3\right)}{\sqrt{x+1}+2}=0\)
\(\Leftrightarrow\left(x-3\right)\left(x+4+\dfrac{12}{\sqrt{x+1}+2}\right)=0\)
\(\Leftrightarrow x-3=0\)
\(\Leftrightarrow x=3\)
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