7r^2+39r+20=0

Solution for 7r^2+39r+20=0 equation:

Simplifying
7r2 + 39r + 20 = 0

Reorder the terms:
20 + 39r + 7r2 = 0

Solving
20 + 39r + 7r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(5 + r)(4 + 7r) = 0

Subproblem 1
Set the factor '(5 + r)' equal to zero and attempt to solve:

Simplifying
5 + r = 0

Solving
5 + r = 0

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

Add '-5' to each side of the equation.
5 + -5 + r = 0 + -5

Combine like terms: 5 + -5 = 0
0 + r = 0 + -5
r = 0 + -5

Combine like terms: 0 + -5 = -5
r = -5

Simplifying
r = -5
Subproblem 2
Set the factor '(4 + 7r)' equal to zero and attempt to solve:

Simplifying
4 + 7r = 0

Solving
4 + 7r = 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 + 7r = 0 + -4

Combine like terms: 4 + -4 = 0
0 + 7r = 0 + -4
7r = 0 + -4

Combine like terms: 0 + -4 = -4
7r = -4

Divide each side by '7'.
r = -0.5714285714

Simplifying
r = -0.5714285714
Solution
r = {-5, -0.5714285714}