(5b+2)(-7b-4)=

Solution for (5b+2)(-7b-4)= equation:

Simplifying
(5b + 2)(-7b + -4) = 0

Reorder the terms:
(2 + 5b)(-7b + -4) = 0

Reorder the terms:
(2 + 5b)(-4 + -7b) = 0

Multiply (2 + 5b) * (-4 + -7b)
(2(-4 + -7b) + 5b * (-4 + -7b)) = 0
((-4 * 2 + -7b * 2) + 5b * (-4 + -7b)) = 0
((-8 + -14b) + 5b * (-4 + -7b)) = 0
(-8 + -14b + (-4 * 5b + -7b * 5b)) = 0
(-8 + -14b + (-20b + -35b2)) = 0

Combine like terms: -14b + -20b = -34b
(-8 + -34b + -35b2) = 0

Solving
-8 + -34b + -35b2 = 0

Solving for variable 'b'.

Factor out the Greatest Common Factor (GCF), '-1'.
-1(8 + 34b + 35b2) = 0

Factor a trinomial.
-1((4 + 7b)(2 + 5b)) = 0

Ignore the factor -1.
Subproblem 1
Set the factor '(4 + 7b)' equal to zero and attempt to solve:

Simplifying
4 + 7b = 0

Solving
4 + 7b = 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 + 7b = 0 + -4

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

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

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

Simplifying
b = -0.5714285714
Subproblem 2
Set the factor '(2 + 5b)' equal to zero and attempt to solve:

Simplifying
2 + 5b = 0

Solving
2 + 5b = 0

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

Add '-2' to each side of the equation.
2 + -2 + 5b = 0 + -2

Combine like terms: 2 + -2 = 0
0 + 5b = 0 + -2
5b = 0 + -2

Combine like terms: 0 + -2 = -2
5b = -2

Divide each side by '5'.
b = -0.4

Simplifying
b = -0.4
Solution
b = {-0.5714285714, -0.4}