4r^2+25r+36=0

Solution for 4r^2+25r+36=0 equation:

Simplifying
4r2 + 25r + 36 = 0

Reorder the terms:
36 + 25r + 4r2 = 0

Solving
36 + 25r + 4r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(4 + r)(9 + 4r) = 0

Subproblem 1
Set the factor '(4 + r)' equal to zero and attempt to solve:

Simplifying
4 + r = 0

Solving
4 + r = 0

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

Add '-4' to each side of the equation.
4 + -4 + r = 0 + -4

Combine like terms: 4 + -4 = 0
0 + r = 0 + -4
r = 0 + -4

Combine like terms: 0 + -4 = -4
r = -4

Simplifying
r = -4
Subproblem 2
Set the factor '(9 + 4r)' equal to zero and attempt to solve:

Simplifying
9 + 4r = 0

Solving
9 + 4r = 0

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

Add '-9' to each side of the equation.
9 + -9 + 4r = 0 + -9

Combine like terms: 9 + -9 = 0
0 + 4r = 0 + -9
4r = 0 + -9

Combine like terms: 0 + -9 = -9
4r = -9

Divide each side by '4'.
r = -2.25

Simplifying
r = -2.25
Solution
r = {-4, -2.25}