1. the sum of the first n odd positive integers is 64. what is the value of n ?

2. how many positive integers between 100 and 200 are divisible by 14 ?

: (

Step-by-step explanation:

The sum of first n odd positive integer is n^2. The nth odd number is 2n-1.

                          i.e. 1 + 3 + + (2n-1) = n^2.  

                                1 + 3 ++ (2n-1) = 64

                                                                n^2 = 64

                                                                    n = 8.

The positive integers between 100 and 200 which are divisible by 14 are 112, 126, 140, 154, 168, 182, 196. It is obtained by the multiples of 14 between 100 and 200.

100 = 7 * 14 + 2

200 = 14 * 14 + 4. The answer is 14 - 7 = 7

The seven numbers are

                        14 * 8 = 112

                        14 * 9 = 126

                        14 * 10 = 140

                        14 * 11 = 154

                        14 * 12 = 168

                        14 * 13 = 182

                        14 * 14 = 196

b

step-by-step explanation:

a difference is the result of subtraction. while each of these expressions has subtraction in it, a difference will be the result when subtraction is the last operation applied in the order of operations for the expression. this means subtraction must be outside of the parenthesis. only b has this.