1) x²-10x+9=0

(x-5)²-4²=0

(x-9)(x-1)=0

[x=9

[x=1

2) x²+2x-3=0

(x+1)-2²=0

(x-1)(x+3)=0

[x=1

[x=-3

3) x²-x-2=0

(x-0,5)²-1,5²=0

(x-2)(x+1)=0

[x=2

[x=-1

4) x²+6x+5=0

(x+3)²-2²=0

(x+1)(x+5)=0

[x=-1

[x=-5