Bài1.Tính hợp lí:
a) (1,11+0,19-2,6):(2,06+0,54)-(\(\dfrac{1}{2}+\dfrac{1}{3}\)):2
b) (2\(\dfrac{1}{3}\)+3,5):(-4\(\dfrac{1}{6}+3\dfrac{1}{7}\))+7,5
1. tìm x
a, 2x - \(\dfrac{1}{2}\) : \(\dfrac{3}{4}\) = \(\dfrac{12}{9}\)
b, x\(^2\) - 2 = 0
2. Cho
A = \(\dfrac{1,11+0,19-13.2}{2,06+0,54}\) - \(\left(\dfrac{1}{2}+\dfrac{1}{4}\right)\) : 2
B = \(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right)\) : \(2\dfrac{23}{26}\)
a, Rút gọn A, B
b, Tìm x ϵ Z để A < x < B
a)
=\(2x-\dfrac{1}{2}=\dfrac{12}{9}\cdot\dfrac{3}{4}=1\)
=\(2x=1+\dfrac{1}{2}=1.5\)
=\(x=1.5:2=0.75\)
b)
=\(x^2=0+2=2\)
TH1:\(x=2\)
TH2:\(x=-2\)
Bài 1:
a: \(2x-\dfrac{1}{2}:\dfrac{3}{4}=\dfrac{12}{9}\)
=>\(2x-\dfrac{1}{2}\cdot\dfrac{4}{3}=\dfrac{4}{3}\)
=>\(2x=\dfrac{4}{3}+\dfrac{2}{3}=\dfrac{6}{3}=2\)
=>x=2/2=1
b: \(x^2-2=0\)
=>\(x^2=2\)
=>\(\left[{}\begin{matrix}x=\sqrt{2}\\x=-\sqrt{2}\end{matrix}\right.\)
Bài 2:
a: \(A=\dfrac{1,11+0,19-13\cdot2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{4}\right):2\)
\(=\dfrac{1,3-26}{2,6}-\dfrac{3}{4}:2\)
\(=-9,5-\dfrac{3}{8}=-\dfrac{79}{8}\)
\(B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):\left(2\dfrac{23}{26}\right)\)
\(=\left(5+\dfrac{7}{8}-2-\dfrac{1}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}\)
\(=\left(3+\dfrac{1}{8}\right)\cdot\dfrac{26}{75}=\dfrac{25}{8}\cdot\dfrac{26}{75}=\dfrac{13}{12}\)
b: A<x<B
=>\(-\dfrac{79}{8}< x< \dfrac{13}{12}\)
mà \(x\in Z\)
nên \(x\in\left\{-9;-8;...;0;1\right\}\)
tính
a)(1,11+0,19-2,6):(2,06+0,54)-(\(\frac{1}{2}+\frac{1}{3}\)):2
b)(\(2\frac{1}{3}+3,5\)):(\(-4\frac{1}{6}+3\frac{1}{7}\))+7,5
Cho:
\(A=\dfrac{1,11+0,19-1,3.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{3}\right):2\)\(B=\left(5\dfrac{7}{3}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
a) Rút gọn A và B
b) Tìm x thuộc Z để A bé hơn x bé hơn B
a: \(A=\dfrac{1.3-2.6}{2.6}-\dfrac{5}{6}\cdot\dfrac{1}{2}=\dfrac{-1}{2}-\dfrac{5}{12}=\dfrac{-11}{12}\)
\(B=\left(\dfrac{22}{3}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}=\dfrac{55}{12}\cdot\dfrac{26}{75}=\dfrac{143}{90}\)
b: Để A<x<B thì \(\dfrac{-11}{12}< x< \dfrac{143}{90}\)
mà x là số nguyên
nên \(x\in\left\{0;1\right\}\)
Cho \(A=\dfrac{1,11+0,19-13.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{4}\right):2\) và \(B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
a, Rút gọn A; B
b, Tìm số nguyên x để A < x < B
Cho \(A=\dfrac{1,11+0,19-13.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{4}\right):2\) và \(B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
a, Rút gọn A; B
b, Tìm số nguyên x để A < x < B
a.
\(A=\dfrac{1,11+0,19-13,2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{4}\right):2\\ =\dfrac{2.2-13,2}{2,6}-\dfrac{3}{4}:2\\ =\dfrac{-11}{2,6}-\dfrac{3}{8}\\ =-\dfrac{55}{13}-\dfrac{3}{8}=-\dfrac{479}{104}\simeq-4,6\\ B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\\ =\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):2\dfrac{23}{26}\\ =\dfrac{13}{12}=1.08\left(3\right)\)
Cho \(A=\dfrac{1,11+0,19-1,3.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{3}\right)\)\(:2\)
\(B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right)\)\(:2\dfrac{23}{26}\)
a. Rút gọn A và B
b. Tìm x để A < x < B
Help me!
a: \(A=\dfrac{1.3-2.6}{2.6}-\dfrac{5}{6}:2=\dfrac{-1}{2}-\dfrac{5}{12}=\dfrac{-11}{12}\)
\(B=\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}=\dfrac{47-18-4}{8}\cdot\dfrac{26}{75}=\dfrac{25}{75}\cdot\dfrac{26}{8}=\dfrac{13}{12}\)
b: Để A<x<B thì -11/12<x<13/12
mà x là số nguyên
nên \(x\in\left\{0;1\right\}\)
Cho A=\(\dfrac{1,11+0,19-13.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{4}:2\right)\)
B=\(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
a)Rút gọn A,B
b)Tìm x\(\in Z\) để A<x<B
a: \(A=\dfrac{1.3-26}{2.6}-\left(\dfrac{1}{2}+\dfrac{1}{8}\right)\)
\(=\dfrac{-19}{2}-\dfrac{3}{8}=\dfrac{-79}{8}\)
\(B=\left(5+\dfrac{7}{8}-2-\dfrac{1}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}=\dfrac{13}{12}\)
b: Vì A<x<B nên \(\dfrac{-79}{8}< x< \dfrac{13}{12}\)
hay \(x\in\left\{-9;-8;...;0;1\right\}\)
Cho:
A=\(\dfrac{1,11+0,19-1,3.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{3}\right):2\)
B=\(\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
a)Rút gọn A và B
b)tìm x\(\in\)Z để A<x<B
a: \(A=\dfrac{1.3-2.6}{2.6}-\dfrac{5}{6}:2=\dfrac{-1}{2}-\dfrac{5}{12}=\dfrac{-11}{12}\)
\(B=\left(\dfrac{47}{8}-\dfrac{9}{4}-\dfrac{1}{2}\right):\dfrac{75}{26}\)
\(=\dfrac{47-18-4}{8}\cdot\dfrac{26}{75}=\dfrac{25}{75}\cdot\dfrac{26}{8}=\dfrac{1}{3}\cdot\dfrac{13}{4}=\dfrac{13}{12}\)
b: Để A<x<B thì \(\dfrac{-11}{12}< x< \dfrac{13}{12}\)
mà x là số nguyên
nên \(x\in\left\{0;1\right\}\)
Bài 1:a) Rút gọn A và B:
\(A=\dfrac{1,11+0,19-1,3.2}{2,06+0,54}-\left(\dfrac{1}{2}+\dfrac{1}{3}\right):2\)
\(B=\left(5\dfrac{7}{8}-2\dfrac{1}{4}-0,5\right):2\dfrac{23}{26}\)
b) Tìm \(x\in Z\) để \(A< x< B\)
Bài 2: Tìm GTNN:
\(M=\left|x-2002\right|+\left|x-2001\right|\)
\(M=\left|x-2002\right|+\left|x-2001\right|\)\(=\left|x-2002\right|+\left|2001-x\right|\ge\left|x-2002+2001-x\right|=\left|-2002+2001\right|=1\)
tức \(M\ge1\) \(\Leftrightarrow\left[{}\begin{matrix}x-2001=0\\x-2002=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2001\\x=2002\end{matrix}\right.\)
Vậy MinM = - 1 \(\Leftrightarrow\left[{}\begin{matrix}x=2001\\x=2002\end{matrix}\right.\)