Tìm GTNN
a. \(\mid x-7\mid\) + \(\mid x+5\mid\)
b. \((2x-1)^2 -3\mid2x-1\mid +2\)
c.\(\mid x^2 + x + 1\mid + \mid x^2 +x -12\mid\)
Những câu hỏi liên quan
Giải phương trình: \(\mid x^2 -2xy+y^2 +3x-2y-1 \mid+4=2x-\mid x^2 -3x+2 \mid\)
Rút gọn biểu thức:
\(2\mid x-3 \mid - \mid 4x -1 \mid\)
Tìm GTNN của các biểu thức:
A mid x-1 mid + mid x-2017 mid
B(x-5)^2+mid x-5mid+2014
Giúp mình nha!!!!!!!!!!!!!!!!!!!!!!!!!
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Tìm GTNN của các biểu thức:
\(A= \mid x-1 \mid + \mid x-2017 \mid\)
\(B=(x-5)^2+\mid x-5\mid+2014\)
Giúp mình nha!!!!!!!!!!!!!!!!!!!!!!!!!
a, Ta có: \(A=\left|x-1\right|+\left|x-2017\right|=\left|x-1\right|+\left|2017-x\right|\)
Áp dụng bất đẳng thức \(\left|a\right|+\left|b\right|\ge\left|a+b\right|\) ta có:
\(A\ge\left|x-1+2017-x\right|=\left|-2016\right|=2016\)
Dấu " = " khi \(\left\{{}\begin{matrix}x-1\ge0\\2017-x\ge0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x\ge1\\x\le2017\end{matrix}\right.\Rightarrow1\le x\le2017\)
Vậy \(MIN_A=2016\) khi \(1\le x\le2017\)
b, Ta có: \(\left\{{}\begin{matrix}\left(x-5\right)^2\ge0\\\left|x-5\right|\ge0\end{matrix}\right.\Rightarrow\left(x-5\right)^2+\left|x-5\right|\ge0\)
\(\Rightarrow B=\left(x-5\right)^2+\left|x-5\right|+2014\ge2014\)
Dấu " = " khi \(\left\{{}\begin{matrix}\left(x-5\right)^2=0\\\left|x-5\right|=0\end{matrix}\right.\Rightarrow x=5\)
Vậy \(MIN_B=2014\) khi x = 5
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Giải phương trình: \(\mid\)x2 -2xy+y2 +3x- 2y-1\(\mid\) +4= 2x-\(\mid\) x2 -3x+2\(\mid\).
Dạng 2: Tìm x
Bài 1: Tìm x biết:
a) dfrac{x-1}{9} dfrac{8}{3} b) (dfrac{3x}{7}+1) : (-4) dfrac{-1}{8} c) x + dfrac{7}{12} dfrac{17}{18}- dfrac{1}{9}
d) 0,5x - dfrac{2}{3}x dfrac{7}{12} e) dfrac{29}{30}- (dfrac{13}{23}+x) dfrac{7}{46} f) (x + dfrac{1}{4}-dfrac{1}{3}) : (2 + dfrac{1}{6}-dfrac{1}{4}) dfrac{7}{46}
g) dfrac{13}{15}- (dfrac{13}{21}+x) . dfrac{7}{12} dfrac{7}{10} h) 2. middfrac{1}{2}x-...
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Dạng 2: Tìm x
Bài 1: Tìm x biết:
a) \(\dfrac{x-1}{9}\) = \(\dfrac{8}{3}\) b) (\(\dfrac{3x}{7}+1\)) : (-4) = \(\dfrac{-1}{8}\) c) x + \(\dfrac{7}{12}\) = \(\dfrac{17}{18}-\) \(\dfrac{1}{9}\)
d) 0,5x - \(\dfrac{2}{3}x\) = \(\dfrac{7}{12}\) e) \(\dfrac{29}{30}-\) (\(\dfrac{13}{23}+x\)) = \(\dfrac{7}{46}\) f) (x + \(\dfrac{1}{4}-\dfrac{1}{3}\)) : (2 + \(\dfrac{1}{6}-\dfrac{1}{4}\)) =\(\dfrac{7}{46}\)
g) \(\dfrac{13}{15}-\) (\(\dfrac{13}{21}+x\)) . \(\dfrac{7}{12}\) = \(\dfrac{7}{10}\) h) 2. \(\mid\)\(\dfrac{1}{2}x-\dfrac{1}{3}\)\(\mid\) \(-\) \(\dfrac{3}{2}\) = \(\dfrac{1}{4}\) i) 3.(\(3x-\dfrac{1}{2}\))3 + \(\dfrac{1}{9}=0\)
Bài 2: Tìm các số nguyên x, y sao cho:
a) \(\dfrac{x}{3}\) = \(\dfrac{4}{y}\) ; b) \(\dfrac{x}{y}\) = \(\dfrac{2}{7}\)
Bài 3: Tìm \(x \in\)Z thỏa mãn: a) 10 + \(\mid\)\(x\)\(\) - 2\(\mid\) = 19 b) \(\mid\)\(x\) -3\(\mid\) < 5 c) 3. \(\mid\)\(x\) + 2\(\mid\) + 1 = 28
Bài 1:
a)
\(\dfrac{x-1}{9}=\dfrac{8}{3}\\ \Leftrightarrow\dfrac{x-1}{9}=\dfrac{24}{9}\\ \Leftrightarrow x-1=24\\ x=24+1\\ x=25\)
b)
\(\left(\dfrac{3x}{7}+1\right):\left(-4\right)=\dfrac{-1}{8}\\ \dfrac{3x}{7}+1=\dfrac{-1}{8}\cdot\left(-4\right)\\ \dfrac{3x}{7}+1=\dfrac{1}{2}\\ \dfrac{3x}{7}=\dfrac{1}{2}-1\\ \dfrac{3x}{7}=\dfrac{-1}{2}\\ 3x=\dfrac{-1}{2}\cdot7\\ 3x=\dfrac{-7}{2}\\ x=\dfrac{-7}{2}:3\\ x=\dfrac{-7}{6}\)
c)
\(x+\dfrac{7}{12}=\dfrac{17}{18}-\dfrac{1}{9}\\ x+\dfrac{7}{12}=\dfrac{5}{6}\\ x=\dfrac{5}{6}-\dfrac{7}{12}\\ x=\dfrac{1}{4}\)
d)
\(0,5x-\dfrac{2}{3}x=\dfrac{7}{12}\\ \dfrac{1}{2}x-\dfrac{2}{3}x=\dfrac{7}{12}\\ x\cdot\left(\dfrac{1}{2}-\dfrac{2}{3}\right)=\dfrac{7}{12}\\ \dfrac{-1}{6}x=\dfrac{7}{12}\\ x=\dfrac{7}{12}:\dfrac{-1}{6}\\ x=\dfrac{-7}{2}\)
e)
\(\dfrac{29}{30}-\left(\dfrac{13}{23}+x\right)=\dfrac{7}{46}\\ \dfrac{29}{30}-\dfrac{13}{23}-x=\dfrac{7}{46}\\ \dfrac{277}{690}-x=\dfrac{7}{46}\\ x=\dfrac{277}{690}-\dfrac{7}{46}\\ x=\dfrac{86}{345}\)
f)
\(\left(x+\dfrac{1}{4}-\dfrac{1}{3}\right):\left(2+\dfrac{1}{6}-\dfrac{1}{4}\right)=\dfrac{7}{46}\\ \left(x-\dfrac{1}{12}\right):\dfrac{23}{12}=\dfrac{7}{46}\\ x-\dfrac{1}{12}=\dfrac{7}{46}\cdot\dfrac{23}{12}\\ x-\dfrac{1}{12}=\dfrac{7}{24}\\ x=\dfrac{7}{24}+\dfrac{1}{12}\\ x=\dfrac{3}{8}\)
g)
\(\dfrac{13}{15}-\left(\dfrac{13}{21}+x\right)\cdot\dfrac{7}{12}=\dfrac{7}{10}\\ \left(\dfrac{13}{21}+x\right)\cdot\dfrac{7}{12}=\dfrac{13}{15}-\dfrac{7}{10}\\ \left(\dfrac{13}{21}+x\right)\cdot\dfrac{7}{12}=\dfrac{1}{6}\\ \dfrac{13}{21}+x=\dfrac{1}{6}:\dfrac{7}{12}\\ \dfrac{13}{21}+x=\dfrac{2}{7}\\ x=\dfrac{2}{7}-\dfrac{13}{21}\\ x=\dfrac{-1}{3}\)
h)
\(2\cdot\left|\dfrac{1}{2}x-\dfrac{1}{3}\right|-\dfrac{3}{2}=\dfrac{1}{4}\\ 2\cdot\left|\dfrac{1}{2}x-\dfrac{1}{3}\right|=\dfrac{1}{4}+\dfrac{3}{2}\\ 2\cdot\left|\dfrac{1}{2}x-\dfrac{1}{3}\right|=\dfrac{7}{4}\\ \left|\dfrac{1}{2}x-\dfrac{1}{3}\right|=\dfrac{7}{4}:2\\ \left|\dfrac{1}{2}x-\dfrac{1}{3}\right|=\dfrac{7}{8}\Rightarrow\left[{}\begin{matrix}\dfrac{1}{2}x-\dfrac{1}{3}=\dfrac{7}{8}\\\dfrac{1}{2}x-\dfrac{1}{3}=\dfrac{-7}{8}\end{matrix}\right.\\ \dfrac{1}{2}x-\dfrac{1}{3}=\dfrac{7}{8}\\ \dfrac{1}{2}x=\dfrac{7}{8}+\dfrac{1}{3}\\ \dfrac{1}{2}x=\dfrac{29}{24}\\ x=\dfrac{29}{24}:\dfrac{1}{2}\\ x=\dfrac{29}{12}\\ \dfrac{1}{2}x-\dfrac{1}{3}=\dfrac{-7}{8}\\ \dfrac{1}{2}x=\dfrac{-7}{8}+\dfrac{1}{3}\\ \dfrac{1}{2}x=\dfrac{-13}{24}\\ x=\dfrac{-13}{24}:\dfrac{1}{2}\\ x=\dfrac{-13}{12}\)
i)
\(3\cdot\left(3x-\dfrac{1}{2}\right)^3+\dfrac{1}{9}=0\\ 3\cdot\left(3x-\dfrac{1}{2}\right)^3=0-\dfrac{1}{9}\\ 3\cdot\left(3x-\dfrac{1}{2}\right)^3=\dfrac{-1}{9}\\ \left(3x-\dfrac{1}{2}\right)^3=\dfrac{-1}{9}:3\\ \left(3x-\dfrac{1}{2}\right)^3=\dfrac{-1}{27}\\ \left(3x-\dfrac{1}{2}\right)^3=\left(\dfrac{-1}{3}\right)^3\\ \Leftrightarrow3x-\dfrac{1}{2}=\dfrac{-1}{3}\\ 3x=\dfrac{-1}{3}+\dfrac{1}{2}\\ 3x=\dfrac{1}{6}\\ x=\dfrac{1}{6}:3\\ x=\dfrac{1}{18}\)
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19 tháng 12 2022 lúc 21:28
B/ Mid – Autumn FestivalThere are hundreds of festival in Vietnam each year. (1)………., Tet holiday, the Mid- Autumn festival is one of the most famous festival and it is a traditional celebration for Vietnamese (2)…………The Mid – Autumn Festival is (3)………….. on the 15th day on the 8th lunar month ( often in late Semtember or early October) in the middle of Autumn and it is celebrated for a whole day. On this day , the adults and the parents prepare a special cake called moon cake along with many ca...
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B/ Mid – Autumn Festival
There are hundreds of festival in Vietnam each year. (1)………., Tet holiday, the Mid- Autumn festival is one of the most famous festival and it is a traditional celebration for Vietnamese (2)…………
The Mid – Autumn Festival is (3)………….. on the 15th day on the 8th lunar month ( often in late Semtember or early October) in the middle of Autumn and it is celebrated for a whole day. On this day , the adults and the parents prepare a special cake called moon cake along with many candies, jellies, grapefruit, bananas, apples, etc. Tha Mid- autumn celebration is an opportunity (4) …………………. Family members to reunite. Young people express their gratitude to the elderly.
Question 1: A. and B. therefore C. besides D. so
Question 2: A. children B. child C. girls D. boys
Question 3: A. held B. remembered C. taken D. done
Question 4: A. on B. for C. in D. at
tìm x
(x+4).11=x.14
giúp mid vs mai mid phải nộp rồi
\(\left(x+4\right).11=x.14\\ \Leftrightarrow11x+44=14x\\ \Leftrightarrow11x-14x=-44\\ \Leftrightarrow-3x=-44\\ \Leftrightarrow x=\dfrac{44}{3}\)
Vậy \(x=\dfrac{44}{3}\)
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\(\left(x+4\right).11=x.14\)
\(11x+44-14x=0\)
\(-3x-44=0\)
\(-3x=44\)
\(x=\dfrac{44}{3}\)
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(x + 4).11 = x.14
11.(x + 4) = 14x
11x = 14x - 44
11x - 14x = 14x - 44 + 14x
-3x = -44
x = 44/3
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Xem thêm câu trả lời
Cho Q = \(\frac{12x-45}{x^2-7x+12}-\frac{x+5}{x-4}+\frac{2x-3}{3-x}\)
a) Rút gọn Q b)Tính giá trị của Q tại \(\mid\)x\(\mid\) = 3
c) Tìm x \(\in\)Z để Q nhận giá trị nguyên
a) Rút gọn :
ĐKXĐ : \(x\ne4,x\ne3\)
Ta có : \(Q=\frac{12x-45}{x^2-7x+12}-\frac{x+5}{x-4}+\frac{2x-3}{3-x}\)
\(=\frac{3\left(4x-15\right)}{\left(x-4\right)\left(x-3\right)}-\frac{\left(x+5\right)\left(x-3\right)}{\left(x-4\right)\left(x-3\right)}-\frac{\left(2x-3\right)\left(x-4\right)}{\left(x-4\right)\left(x-3\right)}\)
\(=\frac{12x-45-x^2-2x+15-2x^2+11x-12}{\left(x-4\right)\left(x-3\right)}\)
\(=\frac{-3x^2+21x-42}{\left(x-4\right)\left(x-3\right)}\)
... Chắc tui rút gọn sai òi :))
2016 . x-2015 +(x-2015) 2 2017 . 2015-x tìm x ; y
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2016 . x-2015 +(x-2015) 2 = 2017 . 2015-x
x-2015 tìm x ; y