There are infinitely many polynomials of order 4 that will give these as the first four numbers and any one of these could be "the" rule.
The simplest rule, based on a polynomial of order 3 is
T(n) = 60*n^3 - 360*n^2 + 673*n - 360 for n = 1, 2, 3, 4.
In order to find this polynomial you need to find the regression equation for the data set (1, 13), (2, 26), (3, 39) and (4, 412).
There are also non-polynomial solutions.
39
26% = 26/100 = 13/50
The one-step equation that equals 13 is x = 13. In this equation, x represents the unknown value that, when solved, will equal 13. This is a simple linear equation that can be solved by performing the inverse operation, which in this case would be x = 13.
26/10 = 13/5 = 2.6
0.5
13/50.
261300
Remember in multiplication that A x B is the same as B x A? Well using this rule we can write that 13 x 2 = 26 and 2 x 13 = 26.
26% = 13/50 as a fraction in its lowest terms
10/26 = 5/13
First, you have to have a lowest common denominator. Eg: 1/2 - 6/13 The lowest common denominator is 26, because 13 * 2 is 26. You multiply 1/2 by 13, to make the denominator 26, which equals 13/26, then multiply 6/13 by 2 to get 12/26. So the equation with the lowest common denominators now plugged in is: 13/26 - 12/26 Subtract the numerators (13 and 12), so the answer is 1/26.
26130