Verified answer

a)4x^2-4x+1=0, D=b^2-4ac==16-4*4*1=0, x=-b/2a=4/2*4=4/8=1/2

b) 5y^2+20y+20=0,D=b^2-4ac=400-4*5*20=0, y=-b/2a=-20/2*5=-2

Verified answer

(2х-1)(2х-1)=0

4х2-2х-2х+1=0

4х2-4х+1=0

Д=16-16=0

х=-б/2а=4/8

х=0,5

5у2+20у+20=0

Д=400-400=0

х=-20/10=-2