Respostas

2014-05-22T23:36:19-03:00
A)x=-b+-√b²-4ac/2a
x=-3+-√3³-4.1(-28)/2.1
x=-3+-√9+112/2
x=-3+-√121/2
x=-3+-11/2
x'=-3+11/2=4
x''-3-11/2=-7
s=4,-7

A melhor resposta!
2014-05-22T23:36:51-03:00
É so usar bhaskara

x =[ -b +/- √(b² - 4ac)] / 2a
  
a) a=1 b=3 c=-28

x= -(3²) +/ √ (3²) - 4*1*(-28) /2*1
x= -9 +/ √9-(-112) /2
x= -9 +/ √121 /2
x= -9 =/ 11 /2
x'= (-9-11)/2
x'= -20/2
x'=-10
x" = (-9+11)/2
x" = 2/2
x"=1
2 4 2
para as letras b e c siga os mxm passos, ok?!?!