Question

calcule discriminante e responda as equaçoes seguintes tem raizes? a)x*+x+8=0 b)3x*-9x-2=0 c)x*-6x-16=0

Answer 1

a) x²+ x + 8=0 a= 1 b= 1 c=8 ∆= b²-4ac ∆=1²-4.1.8 ∆=1-32 ∆=-31 não existem raízes reais B) 3x²-9x-2=O a=3<br />B=-9 c=-2 ∆=b²-4ac ∆=(-9)²-4.3.(-2) ∆=81+24 ∆= 105 x=-b±√∆/2.a x=-(-9)±√105/2.3 x=9±10,25/6 x'=9+10,25/6 x'=19,25/6 x'= 3,208 x"=9-10,25/6 x"=-1,25/6 x"=-0,208 c)x²-6x-16=0 a=1 B=-6 c=-16 ∆=b²-4ac ∆=(-6)²-4.1.(-16) ∆=36+64 ∆=100 x=-b±√∆/2a x=-(-6)±10/2 x=6±10/2 x'=16/2 x'=8 x"=6-10/4 x"=-4/4 x"=-1