a: =>4x^2-12x+9+12x-6=7
=>4x^2+3=7
=>4x^2=4
=>x=1 hoặc x=-1
b: \(\Leftrightarrow\left(x-2\right)\left(x-5\right)=0\)
=>x=2 hoặc x=5
c: \(\Leftrightarrow6x^2-13x+5=0\)
=>6x^2-3x-10x+5=0
=>(2x-1)(3x-5)=0
=>x=5/3 hoặc x=1/2
d:=>(x^2+9)(x^2-2)=0
=>x^2-2=0
hay \(x=\pm\sqrt{2}\)
