2r^2+15r+28=0

Solution for 2r^2+15r+28=0 equation:

Simplifying
2r2 + 15r + 28 = 0

Reorder the terms:
28 + 15r + 2r2 = 0

Solving
28 + 15r + 2r2 = 0

Solving for variable 'r'.

Factor a trinomial.
(4 + r)(7 + 2r) = 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 '(7 + 2r)' equal to zero and attempt to solve:

Simplifying
7 + 2r = 0

Solving
7 + 2r = 0

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

Add '-7' to each side of the equation.
7 + -7 + 2r = 0 + -7

Combine like terms: 7 + -7 = 0
0 + 2r = 0 + -7
2r = 0 + -7

Combine like terms: 0 + -7 = -7
2r = -7

Divide each side by '2'.
r = -3.5

Simplifying
r = -3.5
Solution
r = {-4, -3.5}