Giúp mình bài 5,6 vớii ( kphai bài của mình :>> )
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NN
Nguyễn Ngọc Anh Minh
CTVHS
VIP
6 tháng 9 2021
Ta có \(x< y\Rightarrow a< b\)
\(z-x=\frac{a+b}{2m}-\frac{a}{m}=\frac{a+b-2a}{2m}=\frac{b-a}{2m}\)
\(a< b\Rightarrow b-a>0;m>0\Rightarrow2m>0\Rightarrow z-x=\frac{b-a}{2m}>0\Rightarrow z>x\)
\(z-y=\frac{a+b}{2m}-\frac{b}{m}=\frac{a+b-2b}{2m}=\frac{a-b}{2m}\)
\(a< b\Rightarrow a-b< 0;m>0\Rightarrow2m>0\Rightarrow z-y=\frac{a-b}{2m}< 0\Rightarrow z< y\)
\(\Rightarrow x< z< y\)
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NM
Nguyễn Minh Quang
Giáo viên
6 tháng 9 2021
ta có \(x^2\ge0\forall x\Rightarrow A\left(x\right)=3x^2+1\ge1\forall x\)
hay nói cách khác là A(x) vô nghiệm
NM
Nguyễn Minh Quang
Giáo viên
6 tháng 9 2021
gọi số kg của niken , kẽm và đồng lần lượt là x,y,z để sản xuất ra 68kg bạch đồng
ta có :
\(\hept{\begin{cases}\frac{x}{14}=\frac{y}{15}=\frac{z}{1}\\x+y+z=68\end{cases}}\) áp dụng tính chất của dãy tỉ số bằng nhau ta có : \(\frac{x}{14}=\frac{y}{15}=\frac{z}{1}=\frac{x+y+z}{14+15+1}=\frac{68}{30}\)
\(\Rightarrow\hept{\begin{cases}x=14\times\frac{68}{30}=\frac{476}{15}kg\\y=15\times\frac{68}{30}=34kg\\z=1\times\frac{68}{30}=\frac{34}{15}kg\end{cases}}\)
TV
0
Cái gì vậy chơi bài có qué mà chị cho em kết bạn nhé
oki em