\(\left[{}\begin{matrix}2x-1=0\\x+\dfrac{2}{3}=0\end{matrix}\right.=>\)\(\left[{}\begin{matrix}2x=0+1\\x=0-\dfrac{2}{3}\end{matrix}\right.=>\)\(\left[{}\begin{matrix}x=1:2=\dfrac{1}{2}\\x=-\dfrac{2}{3}\end{matrix}\right.\)
Vậy x ∈ \(\left\{-\dfrac{2}{3};\dfrac{1}{2}\right\}\)
Câu 1:
a) \(\left|\left|3x-3\right|+2x+\left(-1\right)^{2016}\right|=3x+2017^0\)
b) Cho B = \(1+\dfrac{1}{2}.\left(1+2\right)+\dfrac{1}{3}.\left(1+2+3\right)+....+\dfrac{1}{x}.\left(1+2+3+...+4\right)=115\)(x thuộc số tự nhiên khác 0)
Tìm x, biết:
a) \(\left(5x+1\right)^2=\dfrac{36}{49}\)
b) \(\left[\left(-0,5\right)^3\right]^x=\dfrac{1}{64}\)
c) \(2020^{\left(x-2\right).\left(2x+3\right)}=1\)
d) \(\left(x+1\right)^{x+10}=\left(x+1\right)^{x+4}\) với \(x\in Z\)
e) \(\dfrac{3}{4}\sqrt{x}-\dfrac{1}{2}=\dfrac{1}{3}\)
a: (x-1) ( x+5) > 0
b: (x-1) ( x+5) < 0
c) \(\left(x-\dfrac{1}{2}\right)^2=\dfrac{1}{16}\)
d)\(\dfrac{3}{4}-\dfrac{1}{4}\left|x-\dfrac{1}{7}\right|=\dfrac{1}{4}\)
e) 8 ( x+1) - 2 ( 2x + 5 ) = 0
g) ( 6x-1) - ( x + 8 ) =0
h) \(\left|7x-\dfrac{1}{4}\right|=1\)
x) -2x-3=-x+7
Tìm các số nguyên x sao cho tích của 2 số hữu tỉ \(-\dfrac{3}{x-1};\dfrac{x-2}{2}\) là một số nguyên
Giải :
Ta có :
\(-\dfrac{3}{x-1}.\dfrac{x-2}{2}=\dfrac{-3\left(x-2\right)}{\left(x-1\right).2}=\dfrac{-3x+6}{2x-2}\)
\(\dfrac{-3x+6}{2x-2}\) là một số nguyên khi \(-3x+6⋮2x-2\)
\(\Leftrightarrow2\left(-3x+6\right)+3\left(2x-2\right)⋮2x-2\\ \Leftrightarrow-6x+12+6x-6⋮2x-2\\ \Leftrightarrow\left(-6x+6x\right)+\left(12-6\right)⋮2x-2\\ \Leftrightarrow6⋮2x-2\\ \Leftrightarrow2x-2\inƯ\left(6\right)=\left\{1;-1;2;-2;3;-3;6;-6\right\}\\ \Leftrightarrow2x\in\left\{3;1;4;0;5;-1;8;-4\right\}\\ \Leftrightarrow x\in\left\{2;0;4;-2\right\}\)
tìm x biết:
a) / 8-2x/ + /x-5/ = 7
b) \(\left(\dfrac{2}{3}-x\right)\left(\dfrac{1}{2}-2x\right)=0\)
Tìm x biết:
a) \(\dfrac{-32}{\left(-2\right)^x}=4\) f) \(\left(3x-1\right)^3=\dfrac{-8}{27}\)
b) \(\left(\dfrac{1}{2}\right)^{2x-1}=\dfrac{1}{8}\) g) \(\left(2x+3\right)^2=\dfrac{9}{121}\)
c) \(\dfrac{1}{9}.27^x=3^x\) h) \(5^x+5^{x+2}=650\)
d) \(9^x:3^3=\dfrac{1}{243}\) i) \(\left(x-7\right)^{x+1}-\left(x-7\right)=0\)
e) \(\dfrac{x7}{81}=27\) m) \(\left(\dfrac{-3}{4}\right)^{3x-1}=\dfrac{256}{81}\)
Giups e vs
Tính :
a, \(\left(2x-\dfrac{1}{2}\right)^3\)
b, \(\left(\dfrac{x}{2}-y\right)\left(\dfrac{x}{2}+y\right)\)
c\(\left(x+\dfrac{1}{3}\right)^3\)
d\(\left(x-2\right)\left(x^2+2x+4\right)\)
a) \(\left(x-2\right)\left(x+1\right)< 0\)
b) \(\left(x+\dfrac{1}{3}\right)\left(x-1\right)\)> hoặc = 0
Giups e vs
bài 1 : tính :
a, \(\left(2x-\dfrac{1}{2}\right)^3\)
b \(\left(\dfrac{x}{2}-y\right)\left(\dfrac{x}{2}+y\right)\dfrac{ }{ }\)
c\(\left(x+\dfrac{1}{3}\right)^3\)
d\(\left(x-2\right)\left(x^2+2x+4\right)\)
