|2x^2|x-1|| =2x^2+2
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Vì { a2 + a ; a } và { b2 + b ; b } bằng nhau nên ta có các trường hợp sau :
TH1 : a = b \( \implies\) a2 +a = b2 + b ( Luôn đúng )
TH2 : a2 + a = b và b2 + b = a
\( \implies\) a2 + a + b2 + b = a + b
\( \implies\) a2 + b2 = 0 ( 1 )
Ta có : a2 \(\geq\) 0 ; b2 \(\geq\) 0 \( \implies\) a2 + b2 \(\geq\) 0 ( 2 )
Từ ( 1 ) ; ( 2 ) Dấu " = " xảy ra \(\iff\) \(\hept{\begin{cases}a^2=0\\b^2=0\end{cases}}\) \(\iff\) \(\hept{\begin{cases}a=0\\b=0\end{cases}}\) \( \implies\) a = b = 0
KL : a = b
\(\frac{x}{z}=\frac{z}{y}\Leftrightarrow z^2=xy\)
Thay vào ta có: \(\frac{x^2+z^2}{z^2+y^2}=\frac{x^2+xy}{y^2+xy}=\frac{x\left(x+y\right)}{y\left(x+y\right)}=\frac{x}{y}\)
ta có x/z = z/ y
=> x^2/z^2 = z^2/ y^2 = xz/zy = x/y (1)
từ (1) adtcdtsbn
x^2/z^2 = z^2/ y^2 = \(\frac{x^2+z^2}{z^2+y^2}\)(2)
từ (1) (2) => đpcm
vậy................
\(0,3x:\frac{10}{3}=\frac{6}{15}\)
\(\Leftrightarrow0,3x=\frac{3}{25}\)
\(\Leftrightarrow x=\frac{2}{5}\)
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\(\left|2x^2.|x-1|\right|=2x^2+2\)
\(\left|2x^2.\left(x-1\right)\right|=2\left(x^2+1\right)\)
\(\Rightarrow\orbr{\begin{cases}2x^2\left(x-1\right)=2\left(x^2+1\right)\\2x^2\left(x-1\right)=-2\left(x^2+1\right)\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x^2\left(x-1\right)=x^2+1\\x^2\left(x-1\right)=-x^2-1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x^3-x^2=x^2+1\\x^3-x^2=-x^2-1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x^3-2x^2=1\\x^3=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}x^2\left(x-2\right)=1\\x=-1\end{cases}}}\)
Mk chỉ làm đc đến đây thôi còn lại mk chịu