x²-4x-5=0 5x²-13x-6=0 （x+1）²-25x²=0

x²-4x-5=0 5x²-13x-6=0 （x+1）²-25x²=0
x²-4x-5=0 5x²-13x-6=0 （x+1）²-25x²=0

x²-4x-5=0 5x²-13x-6=0 （x+1）²-25x²=0
x²-4x-5=0
1 1
1 -5
(x+1)(x-5)=0
x=-1或x=5
5x²-13x-6=0
1 -3
5 2
(x-3)(5x+2)=0
x=3或x=-2/5
(x+1)²-25x²=0
(x+1+5x)(x+1-5x)=0
(6x+1)(4x-1)=0
x=-1/6或x=1/4