Ta có:
|x+7|\(\ge\)0
Dấu "=" xảy ra \(\Leftrightarrow\)|x+7|=0
\(\Leftrightarrow\)x+7=0
\(\Leftrightarrow\)x=-7
Thay x=-7 vào M ta được:
MinD=\(\frac{-15.\left(-7\right)-68}{3.\left(-7\right)+12}\)
=\(\frac{105-68}{-21+12}\)
=\(\frac{37}{-9}\)
Vậy MinD=\(\frac{37}{-9}\)\(\Leftrightarrow\)x=-7.
Tìm x: \(\frac{3}{\left(x-4\right)\left(x-7\right)}+\frac{6}{\left(x-7\right)\left(x-13\right)}+\frac{15}{\left(x-13\right)\left(x-28\right)}+\frac{1}{x-28}=\frac{-1}{20}\)
Tìm GTNN của D = \(\left|\frac{x}{5}-\frac{y}{7}\right|+\left|2z-3x\right|+\left|xy+yz-500+zx\right|\)
Bài 1: Thực hiện phép tính
a) \(2\frac{1}{2}-\frac{4}{3}+\left(\frac{-1}{3}\right)^4\)
b) \(\frac{1}{7}-\left(-\frac{3}{14}\right)+\frac{1}{2}\)
c) -12:\(\left(\frac{3}{4}-\frac{5}{6}\right)^2\)
d) \(\left(2^2:\frac{4}{3}-\frac{1}{2}\right).\frac{6}{5}-17\)
Bài 2:Tìm x biết
a) \(\frac{4}{7}-x=\frac{1}{3}\)
b) \(x-\frac{2}{3}=-\frac{6}{7}\)
c) \(\left|x-5\right|=7\)
d) \(\frac{2}{3}-1\frac{4}{15}x=\frac{-3}{5}\)
Tìm GTNN:
1,\(\left|x-1\right|+9\)
2,\(\frac{3}{2}.x^2+19\)
3,\(5.\left(x-2\right)^2+12\)
4,\(\frac{1}{2}.\left(x-8\right)^2\)
5,\(\left|x-7\right|+\left|y-8\right|+16\)
6,\(\left|x-1\right|+\left|x-3\right|\)
7,\(3.x^2-x+17\)
8,\(\left|x-1\right|+\left|x-3\right|+\left|x-5\right|\)
Giúp mình với ngày mai mình phải nộp rồi !!!
Tìm \(x,\) biết:
a) \(4\left|3x-1\right|+\left|x\right|-2\left|x-5\right|+7\left|x-3\right|=12\)
b) \(3\left|x+4\right|-\left|2x+1\right|-5\left|x+3\right|+\left|x+9\right|=5\)
c) \( \left|2\frac{1}{5}-x\right|+\left|x-\frac{1}{5}\right|+8\frac{1}{5}=1,2\)
d) \(2\left|x+3\frac{1}{2}\right|+\left|x\right|-3\frac{1}{2}=\left|2\frac{1}{5}-x\right|\)
Tìm GTNN của:
A= \(4.\left|x+3\right|+\left|4x-5\right|+12\)
B= \(\left|x+3\right|+\left|2x-5\right|+\left|x-7\right|\)
Giups mik nha. Mình đang cần gấp
1.tìm x
a.\(\left(3^1_4:x\right).\left(-1^1_4\right)=\frac{-5}{3}-\frac{5}{6}\)
b.\(\frac{-1}{4}-\frac{3}{4}:x=\frac{-11}{36}\)
c.\(\left(-1^1_5+x\right):\left(-3^3_5\right)=\frac{-7}{4}+\frac{1}{4}:\frac{1}{8}\)
d.\(\frac{-22}{15}x+\frac{1}{3}=\left|-\frac{2}{3}+\frac{1}{5}\right|\)
Tim x biết
\(\left|x+\frac{1}{2}\right|+\left|x+\frac{1}{6}\right|+\left|x+\frac{1}{12}\right|+...+\left|x+\frac{1}{110}=11x\right|\)
1.thực hiện phép tính
a.\(25.\left(\frac{-1}{5}\right)^3+\frac{1}{5}-2.\left(\frac{-1}{2}\right)^2-\frac{1}{2}\)
b.\(35^1_6:\left(\frac{-4}{5}\right)-46^1_6:\left(\frac{-4}{5}\right)\)
c.\(\left(\frac{-3}{4}+\frac{2}{5}\right):\frac{3}{7}+\left(\frac{3}{5}+\frac{-1}{4}\right):\frac{3}{7}\)
d.\(\frac{7}{8}:\left(\frac{2}{9}-\frac{1}{18}\right)+\frac{7}{8}.\left(\frac{1}{36}-\frac{5}{12}\right)\)
e.\(\frac{1}{6}+\frac{5}{6}.\frac{3}{2}-\frac{3}{2}+1\)
f.\(\left(-0,75-\frac{1}{4}\right):\left(-5\right)+\frac{1}{15}-\left(\frac{-1}{5}\right):\left(-3\right)\)
