Question

A)
2x-x²=0
b)
¼x²-4x-1=0
c)
-3x²-2x-7=0

Answer 1

A)
2x-x²=0
x(2 - x) = 0
x = 0 lub 2-x = 0
x = 0 lub -x = -2
x = 0 lub x = 2

b)
¼x²-4x-1=0 /4
x² -16x -4 = 0
Δ = (16)² - 4*1*(-4) = 256 + 16 = 272
√Δ= √272 = √16*√17= 4√17
x1 = (4 -4√17): 2*1 = 4( 1-√17): 2 = 2(1-√17)
x2 = (4 +4√17): 2*1 = 4( 1+√17): 2 = 2(1+√17)

c)
-3x²-2x-7=0
Δ = (-2)²-4*(-3)*(-7) = 4 - 84 = -80
Δ < o, więc brak pierwiastków równania