TÌM x, biết:
\(\left|\frac{5}{6}x-16\right|\le0\)
Tìm x,y biết
\(\left\{\frac{1}{2}.x-5\right\}^{10}+\left\{y^2-\frac{1}{4}\right\}^{20}\le0\)
Vì \(\left(\frac{1}{2}x-5\right)^{10}\ge0\)và \(\left(y^2-\frac{1}{4}\right)^{20}\ge0\)
nên \(\left(\frac{1}{2}x-5\right)^{10}+\left(y^2-\frac{1}{4}\right)^{20}=0\)
<=>\(\hept{\begin{cases}\frac{1}{2}x-5=0\\y^2-\frac{1}{4}=0\end{cases}}\)<=>\(\hept{\begin{cases}x=10\\y=\pm\frac{1}{2}\end{cases}}\)
Ta có:\(\hept{\begin{cases}\left\{\frac{1}{2}x-5\right\}^{10}\ge0\forall x\\\left\{y^2-\frac{1}{4}\right\}^{20}\ge0\forall y\end{cases}}\)
Mà \(\left\{\frac{1}{2}x-5\right\}^{10}+\left\{y^2-\frac{1}{4}\right\}^{20}\le0\)
\(\Rightarrow\left\{\frac{1}{2}x-5\right\}^{10}+\left\{y^2-\frac{1}{4}\right\}^{20}=0\)
\(\Leftrightarrow\hept{\begin{cases}\left\{\frac{1}{2}x-5\right\}^{10}=0\\\left\{y^2-\frac{1}{4}\right\}^{20}=0\end{cases}\Leftrightarrow\hept{\begin{cases}\frac{1}{2}x-5=0\\y^2-\frac{1}{4}=0\end{cases}\Leftrightarrow}\hept{\begin{cases}\frac{1}{2}x=5\\y^2=\frac{1}{4}\end{cases}\Leftrightarrow}\hept{\begin{cases}x=10\\y=\pm\frac{1}{2}\end{cases}}}\)
Vậy \(x=10;y=\pm\frac{1}{2}\)
Tìm x, y biết :
\(\left(\frac{1}{2}x-5\right)^{20}+\left(y^2-\frac{1}{4}\right)^{10}\le0\)
Tìm x, y biết:
\(\left(3x-\frac{1}{5}\right)^{2014}+\left(\frac{2}{5}y+\frac{4}{7}\right)\le0\)
Sửa đề \(\left(3x-\frac{1}{5}\right)^{2014}+\left(\frac{2}{5}y+\frac{4}{7}\right)^{2012}\)
Do VT ko âm
\(\Rightarrow\hept{\begin{cases}3x=\frac{1}{5}\\\frac{2}{5}y=-\frac{4}{7}\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{1}{5}.\frac{1}{3}=\frac{1}{15}\\y=-\frac{4}{7}.\frac{5}{2}=\frac{-10}{7}\end{cases}}\)
\(\left(\frac{2}{5}y+\frac{4}{7}\right)^{2016}\) nhé mình thiếu dấu
Vì mũ chẵn luôn lớn hơn hoặc bằng 0
mà theo đề bài
\(\Rightarrow\hept{\begin{cases}3x-\frac{1}{5}=0\\\frac{2}{5}y+\frac{4}{7}=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=\frac{1}{15}\\y=\frac{-10}{7}\end{cases}}\)
Bạn Phạm Tuấn Đạt làm đúng rồi
Tìm x,y biết
\(\left(x-\frac{3}{5}\right)^{2004}+\left(y+2,9\right)^{2006}\le0\)
Tìm x, biết:
a) \(\left(x-3\right)\left(x+2\right)>0\)
b) \(\left(x+5\right)\left(x+1\right)< 0\)
c) \(\frac{\left(x-4\right)}{x+6}\le0\)
d) \(\frac{\left(x-6\right)}{x-7}\ge0\)
a, \(\left(x-3\right)\left(x+2\right)>0\)
th1 : \(\hept{\begin{cases}x-3>0\\x+2>0\end{cases}\Rightarrow\hept{\begin{cases}x>3\\x>-2\end{cases}\Rightarrow}x>3}\)
th2 : \(\hept{\begin{cases}x-3< 0\\x+2< 0\end{cases}\Rightarrow\hept{\begin{cases}x< 3\\x< -3\end{cases}\Rightarrow}x< -3}\)
vậy x > 3 hoặc x < -3
b, \(\left(x+5\right)\left(x+1\right)< 0\)
th1 : \(\hept{\begin{cases}x+5>0\\x+1< 0\end{cases}\Rightarrow\hept{\begin{cases}x>-5\\x< -1\end{cases}\Rightarrow x\in\left\{-4;-3;-2\right\}}}\)
th2 : \(\hept{\begin{cases}x+5< 0\\x+1>0\end{cases}\Rightarrow\hept{\begin{cases}x< -5\\x>-1\end{cases}\Rightarrow}x\in\varnothing}\)
vậy x = -4; -3; -2
c, \(\frac{x-4}{x+6}\le0\)
xét \(\frac{x-4}{x+6}=0\)
\(\Rightarrow x-4=0;x\ne-6\)
\(\Rightarrow x=4\ne-6\)
xét \(\frac{x-4}{x+5}< 0\)
th1 : \(\hept{\begin{cases}x-4< 0\\x+5>0\end{cases}\Rightarrow\hept{\begin{cases}x< 4\\x>-5\end{cases}\Rightarrow}x\in\left\{3;2;1;0;-1;-2;-3;-4\right\}}\)
th2 : \(\hept{\begin{cases}x-4>0\\x+5< 0\end{cases}\Rightarrow\hept{\begin{cases}x>4\\x< -5\end{cases}\Rightarrow x\in\varnothing}}\)
d tương tự c
\(\frac{\left(x-6\right)}{x-7}\ge0\)
Th1: x - 6 < 0
<=> x - 6 + 6 < 0 + 6
<=> x - 6 + 6 > 0 + 6
=> x < 6
Th2: x - 7
<=> x - 7 + 7 < 0 + 7
<=> x - 7 + 7 > 0 + 7
=> x > 7
=> x < 6 hoặc x > 7
Nguyễn Phương Uyên: Làm sai câu a trường hợp 2 rồi nhé! (x + 2) < 0 thì không thể suy ra x < 3 được vì x < 0 + 2 = 2
Siêu sao bóng đá: Giờ nay mới on nên giải hơi chậm nhé! Giải hai bài trước. Bài kia giải sau
a) \(\left(x-3\right)\left(x+2\right)>0\) do đó \(\left(x-3\right)\)và \(\left(x+2\right)\)đồng dấu. Do đó xảy ra hai trường hợp:
TH1: \(\orbr{\begin{cases}\left(x-3\right)>0\\\left(x+2\right)>0\end{cases}\Leftrightarrow\hept{\begin{cases}x>3\\x>-2\end{cases}}}\) Do 3 > -2 nên x > 3
TH2: \(\orbr{\begin{cases}\left(x-3\right)< 0\\\left(x+2\right)< 0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x< 3\\x< -2\end{cases}}\) Do (-2) < 3 nên x < -2
b) \(\left(x+5\right)\left(x+1\right)< 0\) . Do đó ( x + 5) và (x + 1) khác dấu.Nên xảy ra 2 thường hợp:
TH1: \(\orbr{\begin{cases}x+5>0\\x+1< 0\end{cases}\Leftrightarrow\orbr{\begin{cases}x>-5\\x< -1\end{cases}}\Leftrightarrow-5< x< -1}\)
TH2: \(\orbr{\begin{cases}x+5< 0\\x+1>0\end{cases}\Leftrightarrow\orbr{\begin{cases}x< -5\\x>-1\end{cases}\Leftrightarrow}x\in\varnothing}\)
Tìm x,y biết:\(\left(2x-\frac{1}{6}\right)^2+\left|3y+12\right|\le0\)
Ta có: \(\left(2x-\frac{1}{6}\right)^2\ge0\forall x\)
\(\left|3y+12\right|\ge0\forall y\)
=> \(\left(2x-\frac{1}{6}\right)^2+\left|3y+12\right|\ge0\forall x;y\)
=> \(\hept{\begin{cases}2x-\frac{1}{6}=0\\3y+12=0\end{cases}}\)
=> \(\hept{\begin{cases}2x=\frac{1}{6}\\3y=-12\end{cases}}\)
=> \(\hept{\begin{cases}x=\frac{1}{12}\\y=-4\end{cases}}\)
Tìm x,y biết :
a) \(\left(x-\frac{2}{5}\right)^{2010}\)+\(\left(y+\frac{3}{7}\right)^{468}\)\(\le0\)
B) \(\left(x+0,7\right)^{84}\)+ \(\left(y-6,3\right)^{262}\)\(\le0\)
c) \(\left(x-5\right)^{88}\)+\(\left(x+y+3\right)^{468}\)\(\le0\)
Gợi ý: Các biểu thức mũ chẵn đều không âm.
\(a^{2n}+b^{2n}\le0\Leftrightarrow a^{2n}+b^{2n}=0\Leftrightarrow a=b=0\)
a,\(\left(x-\frac{2}{5}\right)^{2010}+\left(y+\frac{3}{7}\right)^{468}\)< \(0\)
Vì \(\left(x-\frac{2}{5}\right)^{2010}\);\(\left(y+\frac{3}{7}\right)^{468}\)đều > \(0\)
=> \(\left(x-\frac{2}{5}\right)^{2010}=0\)
\(\left(y+\frac{3}{7}\right)^{468}=0\)
=> \(\left(x-\frac{2}{5}\right)^{2010}=0^{2010}\)
\(\left(y+\frac{3}{7}\right)^{468}=0^{468}\)
=> \(x-\frac{2}{5}=0\)
\(y-\frac{3}{7}=0\)
=> \(x=\frac{2}{5}\)
\(y=\frac{3}{7}\)
Vậy \(x=\frac{2}{5}\)\(y=\frac{3}{7}\)
b,\(\left(x+0,7\right)^{84}+\left(y-6,3\right)^{262}\)< \(0\)
Vì \(\left(x+0,7\right)^{84}\);\(\left(y-6,3\right)^{262}\)đều > \(0\)
=>\(\left(x+0,7\right)^{84}\) = \(0\)
\(\left(y-6,3\right)^{262}\) = \(0\)
=> \(x+0,7=0\)
\(y-6,3=0\)
=> \(x=0,7\)
\(y=-6,3\)
Vậy \(x=0,7\)\(y=-6,3\)
tìm x biết :
\(\left(\frac{1}{2}x-5\right)^{20}+\left(y^2-\frac{1}{4}\right)^{10}\le0\)
1/2x-5=y2-1/4=0
1/2.x=5 va y2=1/4
x=10 va y=1/2 hoac x=10 va y=-1/2
\(b.\left|\frac{3}{2}x+\frac{1}{9}\right|+\left|\frac{1}{5}y-\frac{1}{2}\right|\le0\)
a) \(\left|3x-\frac{1}{2}\right|+\left|\frac{1}{2}y+\frac{3}{5}\right|=0\)
=>\(3x-\frac{1}{2}=0;\frac{1}{2}y+\frac{3}{5}=0\left(\left|3x-\frac{1}{2}\right|;\left|\frac{1}{2}y+\frac{3}{5}\right|\ge0\right)\)
=>\(x=\frac{1}{6};y=\frac{-6}{5}\)
b)\(\left|\frac{3}{2}x+\frac{1}{9}\right|+\left|\frac{1}{5}y-\frac{1}{2}\right|\le0\)
Ta lại có:
\(\left|\frac{3}{2}x+\frac{1}{9}\right|+\left|\frac{1}{5}y-\frac{1}{2}\right|\ge0\)
=>\(\frac{3}{2}x+\frac{1}{9}=0;\frac{1}{5}y-\frac{1}{2}=0\Rightarrow x=-\frac{2}{27};y=\frac{5}{2}\)