Explicação passo-a-passo:
x²-6x+5=0
a=1
b=-6
c=5
∆=b²-4ac
∆=(-6)²-4*1*5
∆=36-20
∆=16
-b±√∆/2a
6±√16/2*1
6±4/2
x¹=6+4/2=10/2=>5
x²=6-4/2=2/2=>1
*********************
3x²+4x+1=0
a=3
b=4
c=1
∆=b²-4ac
∆=4²-4*3*1
∆=16-12
∆=4
-b±√∆/2a
-4±√4/2*3
-4±2/6
x¹=-4+2/6=-2/6(÷2)=>-1/3
x²=-4-2/6=-6/6=>-1
***************************
x²+3x-28=0
a=1
b=3
c=-28
∆=b²-4ac
∆=3²-4*1*-28
∆=9+112
∆=121
-b±√∆/2a
-3±√121/2*1
-3±11/2
x¹=-3+11/2=8/2=>4
x²=-3-11/2=-14/2=>-7
**********************
-x²+9x-20=0
a=-1
b=9
c=-20
∆=b²-4ac
∆=9²-4*-1*-20
∆=81-80
∆=1
-b±√∆/2a
-9±√1/2*-1
-9±1/-2
x¹=-9+1/-2=-8/-2=>4
x²=-9-1/-2=-10/-2=>5
**********************
3x²-4x+2=0
a=3
b=-4
c=2
∆=b²-4ac
∆=(-4)²-4*3*2
∆=16-24
∆=-8
-b±√∆/2a
4±√-8/2*3
4±√-8/6
Não possui solução no campo dos números reais.
