Need help with 2 & 3 please (precal)

Create a question with this scenario you could ask that could be answered only by graphing or using logarithm. david estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x.

Which of the following vectors are orthogonal to (2,1)? check all that apply

Quadrilateral abcd is a parallelogram with diagonals that intersect at point e. which of the following statements is true?