5b^2-11b-42=0

Solution for 5b^2-11b-42=0 equation:

Simplifying
5b2 + -11b + -42 = 0

Reorder the terms:
-42 + -11b + 5b2 = 0

Solving
-42 + -11b + 5b2 = 0

Solving for variable 'b'.

Factor a trinomial.
(-2 + -1b)(21 + -5b) = 0

Subproblem 1
Set the factor '(-2 + -1b)' equal to zero and attempt to solve:

Simplifying
-2 + -1b = 0

Solving
-2 + -1b = 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 + -1b = 0 + 2

Combine like terms: -2 + 2 = 0
0 + -1b = 0 + 2
-1b = 0 + 2

Combine like terms: 0 + 2 = 2
-1b = 2

Divide each side by '-1'.
b = -2

Simplifying
b = -2
Subproblem 2
Set the factor '(21 + -5b)' equal to zero and attempt to solve:

Simplifying
21 + -5b = 0

Solving
21 + -5b = 0

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

Add '-21' to each side of the equation.
21 + -21 + -5b = 0 + -21

Combine like terms: 21 + -21 = 0
0 + -5b = 0 + -21
-5b = 0 + -21

Combine like terms: 0 + -21 = -21
-5b = -21

Divide each side by '-5'.
b = 4.2

Simplifying
b = 4.2
Solution
b = {-2, 4.2}