x2-25+x(x+5)=0
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a: \(\Leftrightarrow\left(x-5\right)\left(x+1\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=5\\x=-1\\x=1\end{matrix}\right.\)
d: \(\Leftrightarrow\left(x+3\right)\left(x^2-4x+5\right)=0\)
\(\Leftrightarrow x+3=0\)
hay x=-3
a) (x - 3)2 - 5.(x - 2) + 5 = 0.
<=> x^2 - 6x + 9 - 5x + 10 + 5 = 0
<=> x^2 - 11x + 24 = 0
<=> (x-3)(x-8)=0
<=> x = 3 hoặc x = 8
x.(x+5)-x\(^2\)+25=0
x\(^2\)+5x-x\(^2\)+25=0
5x+25=0
5x=-25
x=-5
\(x^2-25-7\left(x-5\right)=0\)
\(\Rightarrow\left(x-5\right)\left(x+5\right)-7\left(x-5\right)=0\)
\(\Rightarrow\left(x-5\right)\left(x-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=5\\x=2\end{matrix}\right.\)
a) x = 1; x = - 1 3 b) x = 2.
c) x = 3; x = -2. d) x = -3; x = 0; x = 2.
mệt
refer
https://www.google.com/search?q=x2+-+25+-+8(5-x)+%3D+0&sourceid=chrome&ie=UTF-8
x2 - 25 - 40 + 8x = 0
<=> x2 + 8x - 65 = 0
<=> x(x + 8) -65 = 0
<=> (x - 65) ( x+8) = 0
\(\Leftrightarrow\left[{}\begin{matrix}x=65\\x=-8\end{matrix}\right.\)
\(\Leftrightarrow7x\left(x+5\right)+\left(x-5\right)\left(x+5\right)=0\\ \Leftrightarrow\left(x-5\right)\left(7x+x+5\right)=0\\ \Leftrightarrow\left(x-5\right)\left(8x+5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=5\\x=-\dfrac{5}{8}\end{matrix}\right.\)
\(\Leftrightarrow x^2+x-5x-5-x^2-6x-9-6=0\\ \Leftrightarrow-10x-20=0\\ \Leftrightarrow x=-2\)
\(x^2-25+x\left(x+5\right)=0\\ \Leftrightarrow\left(x-5\right)\left(x+5\right)+x\left(x+5\right)=0\\ \Leftrightarrow\left(x+5\right)\left(x-5+x\right)=0\\ \Leftrightarrow\left(x+5\right)\left(2x-5\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=-5\\x=\dfrac{5}{2}\end{matrix}\right.\)