Question

rozwiaz rownanie

x^2+2x-3=0

(xdo kwadratu jak by cos^2)

rozwiaz nierownosci

-2x^2+9x-9<0

(-2xtez do kwadratu jak by cos^2)

Answer 1

1.

x^2 + 2x -3 = 0

a = 1

b = 2

c = -3

D(delta) = b^2 - 4ac = 4 +12 = 16

VD = 4

x1 =(-b+VD)/2a =(-2-4)/2 = -3

x2 =(-b+VD)/2a =(-2+4)/2 = 1 

 

x = -3    v    x = 1

 

2.

-2x^2 + 9x - 9 < 0

D = 81 - 72 = 9

VD = 3

x1 = (-9 -3)/(-4) = 3

x2 = (-9 +3)/(-4) = 3/2 = 1,5

 

a < 0 

ramiona paraboli skierowane w ddół

xe (-oo; 1,5) v (3; +oo)