# math

posted by Andre

What is the largest integer n such that 1440/(n^2-1) is an integer?

1. Reiny

factors of 1440
2x720
3x480
4x360
5x288
6x240
8x180
9x160
10x144
12x120
15x96
16x90
18x80
20x72
24x60
30x48
32x45
36x40 ---> that's all of them

values of n^2-1
1,3,8,15,24,35,48,63,80,99,120,143,168,195,288,325,360,399,440,483,529,575,624,675,728

the largest of these that show up in the factor list is 360
and 360 = 19^2 - 1 , where n = 19

## Similar Questions

1. ### Plz help me..just one MATH question

The number 1 is both the square of an integer and the cube of an integer. What is the next larger interger which is both a square and a cube of a positve integer. plz help, the only number i can think of was 0 but its smaller than …
2. ### discrete math

Prove by contradiction that for any even integer a and any odd integer b, 4 does not divide (a^2 + 2b^2). Proposition: That 4k (k is any integer) = a^2 +2b^2, and a is even, and b is odd. But 4k is even (product of any integer and …
3. ### Math

One integer is 4 more than a second integer. Three times the first integer when added to two times the second integer is less than 23. Determine the largest possible values of the two integers.
4. ### Algebra

A.Write and solve an equation to find three consecutive integers with a sum of 126. Let n= the first integer. B. In part A, could you solve the problem by letting n= the middle integer,n-1= the smallest integer, and n+1= the largest …
5. ### Algebra

A.Write and solve an equation to find three consecutive integers with a sum of 126. Let n= the first integer. B. In part A, could you solve the problem by letting n= the middle integer,n-1= the smallest integer, and n+1= the largest …
6. ### la sallle

There are 3 consecutive even integers such that the quotient obtained by dividing twice the largest integer by the smallest integer is three less than three-fifths of the second integer. What are the integers?
7. ### math

An integer is 5 more than another integer. Three times the bigger integer is 11 more than the square of the smaller integer. find the two integers
8. ### Math

Find three consecutive even integers such that the sum of the smallest integer and twice the median integer is 20 more than the largest integer.
9. ### Algebra 1 Polynomials

Suppose n is an integer. Select all statements below that are true: (choose 3) A) n^2 + n is always an even integer*** B) n^2 + n is always an even integer when n is even*** C) n^2 + n is always an even integer when n is odd*** D) …
10. ### math

Which of these is a rational number A.)integer 150 B.)integer 441 C.)integer 200**** D.)integer 250

More Similar Questions