28=b(b-3)

Solution for 28=b(b-3) equation:

Simplifying
28 = b(b + -3)

Reorder the terms:
28 = b(-3 + b)
28 = (-3 * b + b * b)
28 = (-3b + b2)

Solving
28 = -3b + b2

Solving for variable 'b'.

Reorder the terms:
28 + 3b + -1b2 = -3b + 3b + b2 + -1b2

Combine like terms: -3b + 3b = 0
28 + 3b + -1b2 = 0 + b2 + -1b2
28 + 3b + -1b2 = b2 + -1b2

Combine like terms: b2 + -1b2 = 0
28 + 3b + -1b2 = 0

Factor a trinomial.
(7 + -1b)(4 + b) = 0

Subproblem 1
Set the factor '(7 + -1b)' equal to zero and attempt to solve:

Simplifying
7 + -1b = 0

Solving
7 + -1b = 0

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

Add '-7' to each side of the equation.
7 + -7 + -1b = 0 + -7

Combine like terms: 7 + -7 = 0
0 + -1b = 0 + -7
-1b = 0 + -7

Combine like terms: 0 + -7 = -7
-1b = -7

Divide each side by '-1'.
b = 7

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

Simplifying
4 + b = 0

Solving
4 + b = 0

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

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

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

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

Simplifying
b = -4
Solution
b = {7, -4}