b: \(\left|x-\dfrac{3}{5}\right|< \dfrac{1}{3}\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-\dfrac{3}{5}>-\dfrac{1}{3}\\x-\dfrac{3}{5}< \dfrac{1}{3}\end{matrix}\right.\Leftrightarrow\dfrac{4}{15}< x< \dfrac{14}{15}\)
c: \(\left|x+\dfrac{11}{2}\right|>-5.5\)
mà \(\left|x+\dfrac{11}{2}\right|\ge0\forall x\)
nên \(x\in R\)
Tìm x ∈ Z, biết:
a, \(\dfrac{3}{2}\). 4x + \(\dfrac{5}{3}\). 4x+2 = \(\dfrac{3}{2}\). 48 + \(\dfrac{5}{3}\). 410
b, (1/3 + 1/6) . 2x + 2x+1 = 212 + 210
c, (1/2 - 1/3 ) . 6x + 6x+2 = 615 + 618
d, \(\dfrac{5}{3}\). 8x+2 - \(\dfrac{3}{5}\) . 8x = \(\dfrac{5}{3}\). 811 - \(\dfrac{3}{5}\). 89
bài 1 tìm x thuộc Q biết
a. |x|=\(^1_53\) và x<0
b.|x|=-2,1
c.|x-3,5|=5
d. |x+\(\dfrac{3}{4}\)|-\(\dfrac{1}{2}\)=0
e. |x-\(\dfrac{2}{5}\)|+\(\dfrac{1}{2}\)=\(\dfrac{3}{4}\)
f. \(\dfrac{5}{6}\)-|2-x|=\(\dfrac{1}{3}\)
g. (2x-5)^2=9
h. \(\sqrt{3-7x}\)=\(\dfrac{1}{4}\)
i. (\(\dfrac{2}{3}\))^x=\(\dfrac{8}{27}\)
k. (x+\(\dfrac{1}{2}\))^2=\(\dfrac{1}{9}\)
l. \(\dfrac{\left(-3^x\right)}{81}\)=-27
m.\(\left(x-2\right)\)^2x+3=(x-2)^2x+1(x thuộc N)
Bài 1: Tìm x, biết:
a) \(\dfrac{x+2}{18}\)=\(\dfrac{x-5}{9}\)
b)\(\dfrac{x+2}{-20}\)=\(\dfrac{-5}{x+2}\)
c) -10+\(\left(2x-5\right)^3\)=17
Bài 2: Tìm x,y,z biết:
a) \(\dfrac{x}{12}\)=\(\dfrac{y}{-5}\)=\(\dfrac{z}{6}\) và 2x+y-3z=26
b) \(\dfrac{x}{2}\)=\(\dfrac{y}{5}\)=\(\dfrac{z}{4}\) và x.y.z=40
c) \(\dfrac{x+1}{3}\)=\(\dfrac{y+2}{4}\)=\(\dfrac{z+3}{5}\) và x+y+z=18
d) \(\dfrac{x}{2}\)=\(\dfrac{y}{5}\); \(\dfrac{y}{4}\)=\(\dfrac{z}{6}\) và x+y-z=26
e) 4x=3y và \(x^2\)+\(y^2\)=100
1)Tìm x, biết :
\(4.\left[3x-1\right]+\left[x\right]-2.\left[x-5\right]+7.\left[x-3\right]=12\)
\(\left[2\dfrac{1}{5}-x\right]+\left[x-\dfrac{1}{5}\right]+8\dfrac{1}{5}=1,2\)
\(3.\left[x+4\right]-\left[2.x+1\right]-5.\left[x-3\right]+\left[x-9\right]=5\)
\(2\left[x+3\dfrac{1}{2}\right]+\left[x\right]-3\dfrac{1}{2}=\left[2\dfrac{1}{5}-x\right]\)
a,\(\dfrac{x}{2}=\dfrac{y}{3},\dfrac{y}{4}=\dfrac{z}{5}\)và x-y-z=28
b,\(\dfrac{x}{3}=\dfrac{y}{5}=\dfrac{z}{7}\) và \(2x+3y-z=-14\)
c,\(3x=y,5y=4z\) và \(6x+7y+8z=456\)
d,\(\dfrac{x-1}{2005}=\dfrac{3-y}{2006}\)và x-y=4009
Cảm ơn trước nhé!❤❤❤⛇
Tìm x biết:
a) \(\left(-\dfrac{2}{3}\right)^2.x=\left(-\dfrac{2}{3}\right)^5\) ; b) \(\left(-\dfrac{1}{3}\right)^3.x=\dfrac{1}{81}\) ; c) (2x-3)\(^2\) ; d) (3x-2)\(^5\) =-243
Tính và tìm x:
a) \(\dfrac{-1}{4}\).13\(\dfrac{9}{11}\) - 0,25 . 6\(\dfrac{2}{11}\)
b) \(\dfrac{31}{9}\). /x/ - \(\dfrac{5}{2}\) = \(\dfrac{8}{3}\)
2) xác định hệ số a,b của đa thức
P(x)= ax+b, biết
a) P(1)= \(\dfrac{-5}{3}\)
b) P(\(\dfrac{-1}{2}\)) = \(\dfrac{4}{3}\)
tính: a) 12.\(\left\{-\dfrac{2}{3}\right\}^2+\dfrac{4}{3}\) b) 12,5.\(\left\{\dfrac{-5}{7}\right\}+1,5.\left\{\dfrac{-5}{7}\right\}\)
