a) x₁=-2, x₂=2/5
5x²+10x-2x-4=0
5x*(x+2)-2x-4=0
(x+2)*(5x-2)=0
x+2=0
5x-2=0
x=-2
5x-2=0
x=-2
x=2/5
б) x₁=-2/5, x₂=2/5
25x²=4
x²-4/25
x=+2/5
x=-2/5
x=2/5
в) x₁=0, x₂=3
x²=3x
x²-3x=0
x*(x-3)=0
x=0
x-3=0
x=0
x=3
г) x₁=-5, x₂=1
(x+3)²+2(x+3)-4(x+3)-8=0
(x+3)*(x+3+2)-4(x+3)-8=0
(x+3+2)*(x+3-4)=0
(x+5)*(x+3-4)=0
x+5=0
x-1=0
x=-5
x-1=0
x=-5
x=1
