r^2+20r-1125=0

Solution for r^2+20r-1125=0 equation:

Simplifying
r2 + 20r + -1125 = 0

Reorder the terms:
-1125 + 20r + r2 = 0

Solving
-1125 + 20r + r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(-45 + -1r)(25 + -1r) = 0

Subproblem 1
Set the factor '(-45 + -1r)' equal to zero and attempt to solve:

Simplifying
-45 + -1r = 0

Solving
-45 + -1r = 0

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

Add '45' to each side of the equation.
-45 + 45 + -1r = 0 + 45

Combine like terms: -45 + 45 = 0
0 + -1r = 0 + 45
-1r = 0 + 45

Combine like terms: 0 + 45 = 45
-1r = 45

Divide each side by '-1'.
r = -45

Simplifying
r = -45
Subproblem 2
Set the factor '(25 + -1r)' equal to zero and attempt to solve:

Simplifying
25 + -1r = 0

Solving
25 + -1r = 0

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

Add '-25' to each side of the equation.
25 + -25 + -1r = 0 + -25

Combine like terms: 25 + -25 = 0
0 + -1r = 0 + -25
-1r = 0 + -25

Combine like terms: 0 + -25 = -25
-1r = -25

Divide each side by '-1'.
r = 25

Simplifying
r = 25
Solution
r = {-45, 25}