h: \(x^2+5x-6=0\)
=>\(x^2+6x-x-6=0\)
=>(x+6)(x-1)=0
=>\(\left[\begin{array}{l}x+6=0\\ x-1=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=-6\\ x=1\end{array}\right.\)
i: \(\left(2x+3\right)^2-4\left(x+1\right)\left(x-1\right)=49\)
=>\(4x^2+12x+9-4\left(x^2-1\right)=49\)
=>\(4x^2+12x+9-4x^2+4=49\)
=>12x+13=49
=>12x=36
=>x=3
k: \(x^3-x^2=4x^2-8x+4\)
=>\(x^2\left(x-1\right)=4\left(x^2-2x+1\right)=4\left(x-1\right)^2\)
=>\(\left(x-1\right)\left(x^2-4x+4\right)=0\)
=>\(\left(x-1\right)\left(x-2\right)^2=0\)
=>\(\left[\begin{array}{l}x-1=0\\ x-2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=1\\ x=2\end{array}\right.\)
