Bài 3:
a: =>9x^2+12x+4-9x^2+12x-4=5x+38
=>24x=5x+38
=>19x=38
=>x=2
b: \(\Leftrightarrow3x^2-12x+3+9x-9=3x^2+3x-9\)
=>3x^2-3x-6=3x^2+3x-9
=>-6x=-3
=>x=1/2
c: =>x^2+6x+9-x^2+6x-9=6x+18
=>12x=6x+18
=>6x=18
=>x=3
d: \(\Leftrightarrow x^3-3x^2+3x-1-x^3-2x^2-x=10x-5x^2-11x-22\)
=>\(-5x^2+2x-1=-5x^2-x-22\)
=>2x-1=-x-22
=>3x=-21
=>x=-7
e: =>x^3+1-2x=x^3-x
=>-2x+1=-x
=>-x=-1
=>x=1
f: =>\(x^3-6x^2+12x-8+9x^2-1=x^3+3x^2+3x+1\)
=>3x^2+12x-9=3x^2+3x+1
=>9x=10
=>x=10/9
\(Bài2\)
\(a,\left(3x-1\right)\left(x+3\right)=\left(2-x\right)\left(5-3x\right)\\ =>3x^2-x+9x-3=10-5x-6x+3x^2\\ =>3x^2+8x-3-10+11x-3x^2=0\\ =>19x-13=0\\ =>x=\dfrac{13}{19}\\ b,\left(x+5\right)\left(2x-1\right)=\left(2x-3\right)\left(x+1\right)\\ =>2x^2+10x-x-5=2x^2-3x+2x-3\\ =>9x-5+x+3=0\\ =>10x=2\\ =>x=\dfrac{1}{5}\)
\(c,\left(x+1\right)\left(x+9\right)=\left(x+3\right)\left(x+5\right)\\ =>x^2+x+9x+9=x^2+3x+5x+15\\ =>10x+9=8x+15=>10x-8x=15-9\\ =>2x=6\\ =>x=3\\ d,\left(3x+5\right)\left(2x+1\right)=\left(6x-2\right)\left(x-3\right)\\ =>6x^2+10x+3x+5=6x^2-2x-18x+6\\ =>13x+5=-20x+6\\ =>13x+20x=6-5\\ =>33x=1\\ =>x=\dfrac{1}{33}\)
\(e,\left(x+2\right)^2+2\left(x-4\right)=\left(x-4\right)\left(x-2\right)\\ =>x^2+4x+4+2x-8=x^2-4x-2x+8\\ =>6x-4=-6x+8\\ =>12x=12\\ =>x=1\\ f,\left(x+1\right)\left(2x-3\right)-3\left(x-2\right)=2\left(x-1\right)^2\\ =>2x^2+2x-3x-3-3x+6=2\left(x^2-2x+1\right)\\ =>2x^2-4x+3=2x^2-4x+2\\ =>-4x+3=-4x+2\\ =>3=2\left(voli\right)\)
=> pt vô nghiệm
