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\(\left(5x-1\right)^2+2\left(1-5x\right)\left(4+5x\right)+\left(5x+4\right)^2\)
\(=\left(5x-1\right)^2-2\left(5x-1\right)\left(5x+4\right)+\left(5x+4\right)^2\)
\(=\left[\left(5x-1\right)-\left(5x+4\right)\right]^2\)
\(=\left(5x-1-5x-4\right)^2\)
\(=\left(-5\right)^2\)
\(=25\)
(5x-1)^2+2(5x-1)(5x+1)+5(2x-1)
=25x^2-10x+1+2(25x^2-1)+10x-5
=25x^2-4+50x^2-2
=75x^2-6
\(\left(5x-1\right)^2+2\left(5x-1\right)\left(5x+1\right)+5\left(2x-1\right)\)
\(=25x^2-10x+1+2\left(25x^2-1\right)+10x-5\)
\(=25x^2-10x+1+50x^2-2+10x-5\)
\(=\left(25x^2+50x^2\right)+\left(10x-10x\right)+\left(1-2-5\right)\)
\(=75x^2-6\)
\(\Rightarrow5^x\left(1+5+5^2\right)=3875\\ \Rightarrow5^x=\dfrac{3875}{31}=125=5^3\\ \Rightarrow x=3\)
\(C=x^4\left(x-4\right)-x^3\left(x-4\right)+x^2\left(x-4\right)-x\left(x-4\right)+x-1\)
\(C=\left(x-4\right)\left(x^4-x^3+x^2-x\right)+\left(x-1\right)=\left(4-4\right)\left(4^4-4^3+4^2-4\right)+\left(4-1\right)=3\)
a: \(=2x^3:\dfrac{-3}{2}x+4x:\dfrac{3}{2}x-5:\dfrac{3}{2}\)
=-4/3x^2+8/3-10/3
=-4/3x^2-2/3
d: \(\dfrac{3x^3-5x+2}{x-3}=\dfrac{3x^3-9x^2+9x^2-27x+22x-66+68}{x-3}\)
\(=3x^2+9x+22+\dfrac{68}{x-3}\)
a, \(-4x+5+2x-1=3\Leftrightarrow-2x=-1\Leftrightarrow x=\dfrac{1}{2}\)
b, \(-2x+2=2\Leftrightarrow x=0\)
c, \(-2x-6=-8\Leftrightarrow x=1\)
\(\frac{3x+2}{5x+7}=\frac{5x-1}{5x+1}\)
\(\Leftrightarrow\left(3x+2\right)\left(5x+1\right)=\left(5x-1\right)\left(5x+7\right)\)
\(\Leftrightarrow15x^2+3x+10x+2=25x^2+35x-5x-7\)
\(\Leftrightarrow25x^2+30x-7-15x^2-13x-2=0\)
\(\Leftrightarrow10x^2+17x-9=0\)
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