from the beginning we can make up an equation to x=-b/a
1)a+b>0 or a-ax>0. a(1-x)>0 not enough data
2) a-b>0 or a-ax>0. a(1+x)>0 not enough data
1+2) let's sum the equation, because they have the same signs. a>0, from this point we can try the other numbers:
1-x>0, x<1
1+x>0, x>-1
this gives us no answer if x is positive or negative
Answer is E
1)a+b>0 or a-ax>0. a(1-x)>0 not enough data
2) a-b>0 or a-ax>0. a(1+x)>0 not enough data
1+2) let's sum the equation, because they have the same signs. a>0, from this point we can try the other numbers:
1-x>0, x<1
1+x>0, x>-1
this gives us no answer if x is positive or negative
Answer is E