b(b-3)=28

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

Simplifying
b(b + -3) = 28

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

Solving
-3b + b2 = 28

Solving for variable 'b'.

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

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

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

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

Simplifying
-4 + -1b = 0

Solving
-4 + -1b = 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 + -1b = 0 + 4

Combine like terms: -4 + 4 = 0
0 + -1b = 0 + 4
-1b = 0 + 4

Combine like terms: 0 + 4 = 4
-1b = 4

Divide each side by '-1'.
b = -4

Simplifying
b = -4
Subproblem 2
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
Solution
b = {-4, 7}