Attempt if smart please help How many ways are there to form a 4-digit odd number using the digits
3, 4, 5 and 8 without repeating the digits in each number?

12

Step-by-step explanation:

There are 2 ways to choose the last digit (3 or 5), because the number has to be odd.

We're left with 3 digits that we need to arange anyhow. First digit we can choose any of the 3, then any of the 2 left. At the end, there's only one digit to choose.

Answer is 2 * 3 * 2 = 12

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1