Question

Pomocy !!! Rozwiąż nierownosci kwadratowe a)3x2+5x+1=0 b) -6x2-7x+5=0 c)2x2-3x-1=0 d)x(3x+2)+1(3+4x)-3 e)3x2+1=7x f) 5x2=8x-5

Answer 1

a)3x^2+5x+1=0

a=3 b=5 c=1

∆=b^2-4ac

∆=5^2-4∙3∙1

∆=25-12

√∆=√13

 

X1=-b+√∆/2a

X1=-5+√13/2*3

X1=-5+√13/6

X2=-b-√∆/2a

X2=-5-√13/2*3

X2=-5-√13/6

 

 

b)-6x^2-7x+5=0

∆=b^2-4ac

∆=(-7)^2-4∙(-6)∙5

∆=169

√∆=13

X1=-b+√∆/2a

X1=7+13/2*6

X1=5/3

X2=-b-√∆/2a

X2=7+13/2*6

X2=-1/2

 

c)

2x^2-3x-1=0

∆=b^2-4ac

∆=(-3)^2-4∙2∙1

∆=9-8

√∆=1

 

X1=-b+√∆/2a

X1=3+1/2*2

X1=1

X2=-b-√∆/2a

X2=3-1/2*2

X2=1/2

 

d)x(3x+2)+1(3+4x)-3=0

3x^2+2x+3+4x-3=0

3x^2+6x=0

∆=b^2-4∙a∙c

∆=36

√∆=6

X1=-b+√∆/2a

X1=-6+6/2∙3

X1=0

X2=-6-6/6

X2=-2

 

e)5x^2=8x-5

5x^2-8x+5=0

∆=b^2-4∙a∙c

∆=(-8)^2-4∙5∙5

∆=64-60

√∆=2

X1=-b+√∆/2a

X1=8+2/2∙5

X1=1

X2=8-2/2∙5

X2=3/5