Hello i need with concavity of graphs. i have included a picture of the 4 problems i would love to be checked to see if they are correct. my main questions are: what do you do when there's more than 2 concave up/down? and how do you write it if one of the points is open such as in letter a

You would use the union symbol which is a U to glue the intervals together.

For instance, with problem 1 having two concave down intervals. You would write (-8,-4) U (0,4). Note that I'm using parenthesis only and no square brackets at all. The endpoints aren't included as they are open holes. We also don't include any point of inflection (POI). Your other answers are correct. Nice work.

15

step-by-step explanation:

we are given the following expression and we are to solve it and find the product:

-13 × (-5)

solving the given expression in the standard order of solving a mathematical expression, beginning with the opening of brackets and then multiplying the terms and changing their signs.

-3 × -5 = 15 (answer is positive because when negative is multiplied with negative, it gives a positive answer)