Question

What's the answer? Plz explain.

Answer 1

This can be a tricky question because you may think that the minimum possible value is -∞ because the function goes on infinitely. The key thing to note here that the question is asked on a closed interval. If it were an open interval, -∞ would be right. But, since it's bound on both sides, we know that A is NOT the answer. The function never goes below -2 during the interval -4 ≤ x ≤ 6 . So, B or -4 is not the answer. Clearly D is not the answer as 1 is not the lowest value the function takes on.

C, -2 is the best choice because that is the function's lowest value in the given interval. Thus, your answer is C.

Answer 2

Remark

Watch out for the -4<=x<=6 thing. It causes lot's of problems if you are not careful.

Solution.

The second best answer is A and if that restriction, -4<=x<=6, wasn't there, the answer would be A.

When y = - 4, the x value falls outside the restricted domain ( -4<=x<=6) we have been given. so B is not the answer.

When x = - 4 you have to read straight down to see what the y value is. It is - 2. So this is your answer. Only exactly what is the answer. They ask for the minimum value and that is a y value in this case.

So the answer is C <<<<< Answer.

When y = 1 , x = - 2 1/2. That is within the domain, but it is not the minimum value so D is wrong.