a^2+5a-84=0

Solution for a^2+5a-84=0 equation:

Simplifying
a2 + 5a + -84 = 0

Reorder the terms:
-84 + 5a + a2 = 0

Solving
-84 + 5a + a2 = 0

Solving for variable 'a'.

Factor a trinomial.
(-12 + -1a)(7 + -1a) = 0

Subproblem 1
Set the factor '(-12 + -1a)' equal to zero and attempt to solve:

Simplifying
-12 + -1a = 0

Solving
-12 + -1a = 0

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

Add '12' to each side of the equation.
-12 + 12 + -1a = 0 + 12

Combine like terms: -12 + 12 = 0
0 + -1a = 0 + 12
-1a = 0 + 12

Combine like terms: 0 + 12 = 12
-1a = 12

Divide each side by '-1'.
a = -12

Simplifying
a = -12
Subproblem 2
Set the factor '(7 + -1a)' equal to zero and attempt to solve:

Simplifying
7 + -1a = 0

Solving
7 + -1a = 0

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

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

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

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

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

Simplifying
a = 7
Solution
a = {-12, 7}