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2010-02-23T19:42:08+01:00
A)x² -2x =0
x(x-2)=0
x=0 x-2=0
x=2

B) 3x²+8x=0
x(3x-8)=0
x=0 3x-8=0
3x=8
x=2 i2/3

C) 4x²- x/2 = 8 |*2
8x²-x-16
Δ=513 √Δ=√513
x₁=1-√513/16
x₂=1+√513/16

D) x²=-7x
x²+7x=0
x(x+7)=0
x=0 x+7=0
x=-7

E) -5x-4x² =0
x(4x-5)=0
x=0 4x-5=0
4x=5
x=1 i1/4

F) 1/3 x² =5x
1/3x²-5x=0
x(1/3-5x)=0
x=0 1/3-5x=0
-5x=-1/3
x=1/15

g)-2/7 x²+ 2x=0
x(-2/7x+2)=0
x=0 -2/7x+2=0
-2/7x=-2
x=7

h)x² +2/2 =4x+1
x²-4x+2=0
Δ=16-8=8 √Δ=2√2
x₁=4-2√2/2 x₂=4+2√2/2
x₁=2-√2 x₂=2+√2