Opgave 1

a.

x²-4x-5=0
(x-2)²-4-5=0
(x-2)²-9=0
(x-2)²=9
x-2=-3 of x-2=3
x=-1 of x=5

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b.

x²-4x-16=0
(x-2)²-4-16=0
(x-2)²-20=0
(x-2)²=20
x-2=-$\sqrt{20}$ of x-2=$\sqrt{20}$
x=2-$\sqrt{20}$ of x=2+$\sqrt{20}$
x=2-2$\sqrt{5}$ of x=2+2$\sqrt{5}$

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c.

x²-4x+4=0
(x-2)²-4+4=0
(x-2)²=0
x-2=0
x=2

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Opgave 2

a.

y=x²-4x-5
y=(x-2)²-4-5
y=(x-2)²-9
Top (2,-9)

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b.

y=x²-4x-16
y=(x-2)²-4-16
y=(x-2)²-20
Top (2,-20)

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c.

y=x²-4x+4
y=(x-2)²-4+4
y=(x-2)²
Top (2,0)

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