Respostas

2014-05-08T10:15:44-03:00
X2- 20x=0
x(x-20)=0
x'= 0
x-20=0
x''=20

2x2-11x=0
x(2x-11)=0
x'= 0
2x-11=0
x= 11/2

x'= 0
x(x+9)= 0
x+9= 0
x"= -9

-7x2+7x= 0 : (-1)
x2- x= 0
x'= 0
x(x-1)=0
x"= 1