a)f(x)=x²+16x+39
x²+16x+39=0
x'=[-16+√(16²-4*1*39)]/2
x'=[-16+√(256-156)]/2
x'=[-16+√(256-156)]/2=[-16+10]/2=-3
x''=[-16-√(256-156)]/2=[-16-10]/2=-13
x'=-3 e x''=-13
b)f(x)=2x²+10x+12
2x²+10x+12=0
divida tudo por 2
x²+5x+6=0
x'=[-5+√(25-24)]/2= (-5+1)/2=-2
x''=[-5-√(25-24)]/2= (-5-1)/2=-3
x'=-2 e x''=-3
c)f(x)=x²+5x+6
x²+5x+6=0
x'=[-5+√(5²-4*1*6)]/2=(-5+1)/2=-2
x''=[-5-√(5²-4*1*6)]/2=(-5-1)/2=-3
x'=-2 e x''=-3
***as raízes da b e c são iguais mesmo
