Find the second and eleventh terms of the sequence described by the explicit formula: A(n)=-9+(n-1) (3)

The highest common factor of 132 and 220

45% of the trees in a park are apple trees. there are 27 apple trees in the park. how many trees are in the park in all?

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).