\(\left|3x+7\right|\ge0\\ \Leftrightarrow4\left|3x+7\right|\ge0\\ \Leftrightarrow4+\left|3x+7\right|+3\ge3\\ \Leftrightarrow\dfrac{15}{4\left|3x+7\right|+3}\le\dfrac{15}{3}=5\\\Leftrightarrow5+\dfrac{15}{4\left|3x+7\right|+3}\le5+5=10\)
Dấu "=" xảy ra khi:
\(\left|3x+7\right|=0\\ \Leftrightarrow3x+7=0\\ \Leftrightarrow3x=-7\\ \Leftrightarrow x=-\dfrac{7}{3}\)
Vậy ...
tim gtln 5+\(\dfrac{15}{4\left|3x+7\right|+3}\)
a, 3-2 | 4x-5| = \(\dfrac{2}{6}\)
b, | 4-7x | - \(\dfrac{3}{2}\) : 5 = | -1 \(\dfrac{1}{3}\) |
c, ( 7-3x ) ( 2x+ 1 )= 0
d, 2x (5-3x) > 0
e, ( 4-2x) ( 5x +3 ) < 0
g, | 3x + 1 | + | 1 -3x | = 0
mọi người giúp mình nha mình đang cần gấp lắm
Tìm x, biết:
a, \(|2x-3|-\dfrac{5}{2}=\dfrac{1}{3}\)
b, \(|x-1|+3x=1\)
c, \(|5x-3|-x=7\)
d, \(|2x+1|+|x+8|=4x\)
e, \(|3x+2|+|4x+3|=2x-4\)
f, \(|2x-4|+|8-4x|=15\)
g, \(|x^2-2x|=x\)
1, \(\dfrac{x}{3}=\dfrac{y}{2}\); \(\dfrac{x}{5}=\dfrac{x}{7}\) và x +2y = -112
2, 2x = 3y; 5y = 7z và 3x - 7y + 5z = 30
3, \(\dfrac{x}{y}=\dfrac{10}{9};\) \(\dfrac{y}{z}=\dfrac{3}{4}\) và x +2y - 3z = -48
Làm giúp, cần gấp
Câu 1: Tinh
\(A=\left(\dfrac{3}{5}\right)^2.5^2-\left(2\dfrac{1}{4}\right)^3:\left(\dfrac{3}{4}\right)^3+\dfrac{1}{2}\)
\(B=\left[\dfrac{4}{11}.\left(\dfrac{1}{25}\right)^0+\dfrac{7}{22}.2\right]^{2010}-\left(\dfrac{1}{2^2}:\dfrac{8^2}{4^4}\right)^{2009}\)
\(\dfrac{7}{8}.\left(\dfrac{2}{12}+\dfrac{4}{10}\right)\)
\(\dfrac{3}{2}-\dfrac{5}{6}:\left(\dfrac{1}{2}\right)^2+\sqrt{4}\)
Câu 2: Tim x
\(2.x-\dfrac{5}{4}=\dfrac{20}{15}\)
\(\left(x+\dfrac{1}{3}\right)^3=\left(\dfrac{-1}{8}\right)\)
1,tìm x:
a,\(\dfrac{3}{4}-|2x+1|=\dfrac{7}{8}\)
b,\(2.|2x-3|=\dfrac{1}{2}\)
c,\(7,5-3.|5-2x|=-4,5\)
d,\(|x+\dfrac{4}{15}|-|-3,75|=-|-2,15|\)
giúp mình nha mọi người
Tính giá trị của biểu thức:
\(\dfrac{\dfrac{3}{4}-\dfrac{3}{5}+\dfrac{3}{7}+\dfrac{3}{11}}{\dfrac{13}{4}-\dfrac{13}{5}+\dfrac{13}{7}+\dfrac{13}{11}}\)
Hnay nộp rồi, nhanh nha
tìm x
a)\(\dfrac{3}{4}\)+\(\dfrac{1}{4}\):x=\(\dfrac{2}{5}\)
b)|x-1|+3x=1
c)(x-3):4=4:(x-3)
1.(x+1)/35 + (x+3)/33 = (x+5)/33 + (x+7)/20
2. (X+1)/12+ (X+2)/13 = (X+3)/14+ (X+4)/15
3. (X-85)/15+ (X-75)/13+(X-67)/11+ (X-64)/9=10
4. (X-1)/13-(2X-13)/15=(3X-15)/27- (4X-27)/29
