\(Bài.1\left(NB\right)\\ a,4x^2-9=0\\ \Leftrightarrow4x^2=9\\ \Leftrightarrow x^2=\dfrac{9}{4}=\left(\dfrac{3}{2}\right)^2=\left(-\dfrac{3}{2}\right)^2\\ Vậy:x=\dfrac{3}{2}.hoặc.x=-\dfrac{3}{2}\\ b,x^2-10x=-25\\ \Leftrightarrow x^2-10x+25=0\\ \Leftrightarrow x^2-2.x.5+5^2=0\\ \Leftrightarrow\left(x-5\right)^2=0\\ \Leftrightarrow x-5=0\\ \Leftrightarrow x=5\\ Vậy:x=5\)
2:
a: =>x^2-10x+25+x^2-9-2(x^2+2x+1)=0
=>2x^2-10x+16-2x^2-4x-2=0
=>-14x+14=0
=>14x=14
=>x=1
b: =>25x^2-10x+1-25x^2+16=7
=>-10x=-10
=>x=1
3:
a: =>(2x-5-2x)(2x-5+2x)=0
=>-5(4x-5)=0
=>4x-5=0
=>x=5/4
b: =>(3x-1-x-1)(3x-1+x+1)=0
=>(2x-2)(4x)=0
=>x=0 hoặc x=1
\(Bài.2\left(TH\right):\\ a,\left(x-5\right)^2+\left(x-3\right)\left(x+3\right)-2\left(x+1\right)^2=0\\ \Leftrightarrow\left(x^2-10x+25\right)+\left(x^2-9\right)-2\left(x^2+2x+1\right)=0\\ \Leftrightarrow x^2+x^2-2x^2-10x-4x=-25+9+2\\ \Leftrightarrow-14x=-14\\ \Leftrightarrow x=\dfrac{-14}{-14}=1\\ Vậy:x=1\\ b,\left(5x-1\right)^2-\left(5x-4\right)\left(5x+4\right)=7\\ \Leftrightarrow\left(25x^2-10x+1\right)-\left(25x^2-16\right)-7=0\\ \Leftrightarrow25x^2-25x^2-10x=7-1-16\\ \Leftrightarrow-10x=-10\\ \Leftrightarrow x=\dfrac{-10}{-10}=1\\ Vậy:x=1\)
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