a: =>x=(-2/3)^5:(-2/3)^2=(-2/3)^3=-8/27
b: =>x*(-1/3)^3=(-1/3)^4
=>x=-1/3
d: =>3x-2=-3
=>3x=-1
=>x=-1/3
a: =>x=(-2/3)^5:(-2/3)^2=(-2/3)^3=-8/27
b: =>x*(-1/3)^3=(-1/3)^4
=>x=-1/3
d: =>3x-2=-3
=>3x=-1
=>x=-1/3
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, \(\dfrac{\left(-3\right)^x}{81}=-27\)
b, \(2^{x-1}=16\)
c, \(\left(x-1\right)^2=25\)
d, \(0,2-\left|4,2-2x\right|=0\)
e, \(1\dfrac{2}{3}:\dfrac{x}{4}=6:0,3\)
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)
\(\left(\dfrac{32}{243}\right)^x=\left(\dfrac{3}{2}\right)^{-1}\)
Câu 1:Thực hiện phép tính(tính một cách hợp lí nếu có thể):
a)\(\dfrac{1}{2}-\dfrac{-3}{6}=+\dfrac{5}{3}-\dfrac{9}{12}\)
b)\(\begin{matrix}&\left(\dfrac{-2}{3}\right)\end{matrix}.\dfrac{3}{11}+\left(\dfrac{-16}{9}\right):\dfrac{11}{3}\)
c)\(\begin{matrix}&\left(\dfrac{2}{3}\right)^0\end{matrix}-\sqrt{9+}\left(-\dfrac{^{ }1}{2}\right)^2\)
tính: a) 12.\(\left\{-\dfrac{2}{3}\right\}^2+\dfrac{4}{3}\) b) 12,5.\(\left\{\dfrac{-5}{7}\right\}+1,5.\left\{\dfrac{-5}{7}\right\}\)
Thực hiện phép tính biết:
a) \(\dfrac{2}{3}:\dfrac{-5}{3}+\dfrac{7}{5}\)
b) \(3^7:3^5+\left|-2\right|.5^2\)
Bài 1:Tìm GTLN của các bểu thức:
a) A=5-3.(2x-1)2
b) B=\(\dfrac{1}{2.\left(x-1\right)^2+3}\)
c) C=\(\dfrac{x^2+8}{x^2+2},x\in Z\)
Bài 2: Tìm x sao cho:
a)(x-1)(x-2)>0
b) (x-2)2.(x+1).(x-4)<0
c) \(\dfrac{5}{x}< x\)
Làm hộ mình nhé
HElP ME!!
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