(n-1)*5=15

Solution for (n-1)*5=15 equation:

Simplifying
(n + -1) * 5 = 15

Reorder the terms:
(-1 + n) * 5 = 15

Reorder the terms for easier multiplication:
5(-1 + n) = 15
(-1 * 5 + n * 5) = 15
(-5 + 5n) = 15

Solving
-5 + 5n = 15

Solving for variable 'n'.

Move all terms containing n to the left, all other terms to the right.

Add '5' to each side of the equation.
-5 + 5 + 5n = 15 + 5

Combine like terms: -5 + 5 = 0
0 + 5n = 15 + 5
5n = 15 + 5

Combine like terms: 15 + 5 = 20
5n = 20

Divide each side by '5'.
n = 4

Simplifying
n = 4