(x-15)(x-3)=0

Solution for (x-15)(x-3)=0 equation:

Simplifying
(x + -15)(x + -3) = 0

Reorder the terms:
(-15 + x)(x + -3) = 0

Reorder the terms:
(-15 + x)(-3 + x) = 0

Multiply (-15 + x) * (-3 + x)
(-15(-3 + x) + x(-3 + x)) = 0
((-3 * -15 + x * -15) + x(-3 + x)) = 0
((45 + -15x) + x(-3 + x)) = 0
(45 + -15x + (-3 * x + x * x)) = 0
(45 + -15x + (-3x + x2)) = 0

Combine like terms: -15x + -3x = -18x
(45 + -18x + x2) = 0

Solving
45 + -18x + x2 = 0

Solving for variable 'x'.

Factor a trinomial.
(3 + -1x)(15 + -1x) = 0

Subproblem 1
Set the factor '(3 + -1x)' equal to zero and attempt to solve:

Simplifying
3 + -1x = 0

Solving
3 + -1x = 0

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

Add '-3' to each side of the equation.
3 + -3 + -1x = 0 + -3

Combine like terms: 3 + -3 = 0
0 + -1x = 0 + -3
-1x = 0 + -3

Combine like terms: 0 + -3 = -3
-1x = -3

Divide each side by '-1'.
x = 3

Simplifying
x = 3
Subproblem 2
Set the factor '(15 + -1x)' equal to zero and attempt to solve:

Simplifying
15 + -1x = 0

Solving
15 + -1x = 0

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

Add '-15' to each side of the equation.
15 + -15 + -1x = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -1x = 0 + -15
-1x = 0 + -15

Combine like terms: 0 + -15 = -15
-1x = -15

Divide each side by '-1'.
x = 15

Simplifying
x = 15
Solution
x = {3, 15}