r^2-15r=16

Solution for r^2-15r=16 equation:

Simplifying
r2 + -15r = 16

Reorder the terms:
-15r + r2 = 16

Solving
-15r + r2 = 16

Solving for variable 'r'.

Reorder the terms:
-16 + -15r + r2 = 16 + -16

Combine like terms: 16 + -16 = 0
-16 + -15r + r2 = 0

Factor a trinomial.
(-1 + -1r)(16 + -1r) = 0

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

Simplifying
-1 + -1r = 0

Solving
-1 + -1r = 0

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

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

Combine like terms: -1 + 1 = 0
0 + -1r = 0 + 1
-1r = 0 + 1

Combine like terms: 0 + 1 = 1
-1r = 1

Divide each side by '-1'.
r = -1

Simplifying
r = -1
Subproblem 2
Set the factor '(16 + -1r)' equal to zero and attempt to solve:

Simplifying
16 + -1r = 0

Solving
16 + -1r = 0

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

Add '-16' to each side of the equation.
16 + -16 + -1r = 0 + -16

Combine like terms: 16 + -16 = 0
0 + -1r = 0 + -16
-1r = 0 + -16

Combine like terms: 0 + -16 = -16
-1r = -16

Divide each side by '-1'.
r = 16

Simplifying
r = 16
Solution
r = {-1, 16}