x²+4x-2=0,x²-4x+1=0,(x+√5)(x-√5)=20,x²+6x+5=8x+7,25(2x-1)²-16=0,

x²+4x-2=0,x²-4x+1=0,(x+√5)(x-√5)=20,x²+6x+5=8x+7,25(2x-1)²-16=0,

x²+4x-2=0
x²+4x=2
x²+4x+4=2+4
(x+2)²=6
x+2=±√6
X + 2 = √ 6 or x + 2 = - √ 6
x1=-2+√6 ,x2=-2-√6
x²-4x+1=0
x²-4x=-1
x²-4x+4=-1+4
(x-2)²=3
x-2=±√3
X-2 = √ 3 or X-2 = - √ 3
x1=2+√3 ,x2=2-√3
(x+√5)(x-√5)=20
x²-√5²=20
x²-5=20
x²=25
x=±5
x1=5,x2=-5
x²+6x+5=8x+7
x²+6x-8x=7-5
x²-2x=2
x²-2x+1=2+1
(x-1)²=3
x-1=±√3
X-1 = √ 3 or X-1 = - √ 3
x1=1+√3 ,x2=1-√3
25(2x-1)²-16=0
25(2x-1)²=16
(2x-1)²=16/25
2x-1=±√(16/25)
2x-1=±4/5
2x-1=±0.8
2x-1 = 0.8 or 2x-1 = - 0.8
x1=0.9 ,x2=0.1