a^2+21a-540=0

Solution for a^2+21a-540=0 equation:

Simplifying
a2 + 21a + -540 = 0

Reorder the terms:
-540 + 21a + a2 = 0

Solving
-540 + 21a + a2 = 0

Solving for variable 'a'.

Factor a trinomial.
(-36 + -1a)(15 + -1a) = 0

Subproblem 1
Set the factor '(-36 + -1a)' equal to zero and attempt to solve:

Simplifying
-36 + -1a = 0

Solving
-36 + -1a = 0

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

Add '36' to each side of the equation.
-36 + 36 + -1a = 0 + 36

Combine like terms: -36 + 36 = 0
0 + -1a = 0 + 36
-1a = 0 + 36

Combine like terms: 0 + 36 = 36
-1a = 36

Divide each side by '-1'.
a = -36

Simplifying
a = -36
Subproblem 2
Set the factor '(15 + -1a)' equal to zero and attempt to solve:

Simplifying
15 + -1a = 0

Solving
15 + -1a = 0

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

Add '-15' to each side of the equation.
15 + -15 + -1a = 0 + -15

Combine like terms: 15 + -15 = 0
0 + -1a = 0 + -15
-1a = 0 + -15

Combine like terms: 0 + -15 = -15
-1a = -15

Divide each side by '-1'.
a = 15

Simplifying
a = 15
Solution
a = {-36, 15}