Question

Resolva as equações do 2° grau .
a) x2-x-4=0

B) -2x2-3x=0

Answer 1

x²-x-4=0
a formula é  x=-b+-√b²-4*a*c/2*a
x²=a=1
-x=b-1
-4=c-4
colocando na formula
x=1+-√-1²-4*1*-4/2*1
x=1+-√1+16/2
x=1+-√17/2
x=1+-17/2
x=1+17/2  x=18/2  x¹=9
x=1-17/2  x=-16/2  x²=-8

-2x²-3x+0=0
a=-2
b=-3
c=0

x=-b+-√b²-4*a*c/2*a
x=3+-√9-4*-2*0/2*-2
x=3+-√9+0/-4
x=3+-3/-4
x=3+-3/-4
x=6/-4   x=3/-2
x=3-3/-4
x=0/-4  x=1