I would feel better about answering if you had shown some attempt yourself!
Consider the function with
i) a= 0, b= 2
ii) a= -2, b= 0
suppose that f : R-->R is strictly concave up, strictly increasing function with a zero t satisfying a<t< b
Which of the following are true
1.f(b)<0
2.f(b)=0
3.f(b)>0
4.f(a)<0
5.f(a)=0
6.f(a)>0
7.impossible to determine
can someone help me with this