(b+7)(b-4)=

Solution for (b+7)(b-4)= equation:

Simplifying
(b + 7)(b + -4) = 0

Reorder the terms:
(7 + b)(b + -4) = 0

Reorder the terms:
(7 + b)(-4 + b) = 0

Multiply (7 + b) * (-4 + b)
(7(-4 + b) + b(-4 + b)) = 0
((-4 * 7 + b * 7) + b(-4 + b)) = 0
((-28 + 7b) + b(-4 + b)) = 0
(-28 + 7b + (-4 * b + b * b)) = 0
(-28 + 7b + (-4b + b2)) = 0

Combine like terms: 7b + -4b = 3b
(-28 + 3b + b2) = 0

Solving
-28 + 3b + b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(-7 + -1b)(4 + -1b) = 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 + -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
Solution
b = {-7, 4}