18a=40-a^2

Solution for 18a=40-a^2 equation:

Simplifying
18a = 40 + -1a2

Solving
18a = 40 + -1a2

Solving for variable 'a'.

Reorder the terms:
-40 + 18a + a2 = 40 + -1a2 + -40 + a2

Reorder the terms:
-40 + 18a + a2 = 40 + -40 + -1a2 + a2

Combine like terms: 40 + -40 = 0
-40 + 18a + a2 = 0 + -1a2 + a2
-40 + 18a + a2 = -1a2 + a2

Combine like terms: -1a2 + a2 = 0
-40 + 18a + a2 = 0

Factor a trinomial.
(-20 + -1a)(2 + -1a) = 0

Subproblem 1
Set the factor '(-20 + -1a)' equal to zero and attempt to solve:

Simplifying
-20 + -1a = 0

Solving
-20 + -1a = 0

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

Add '20' to each side of the equation.
-20 + 20 + -1a = 0 + 20

Combine like terms: -20 + 20 = 0
0 + -1a = 0 + 20
-1a = 0 + 20

Combine like terms: 0 + 20 = 20
-1a = 20

Divide each side by '-1'.
a = -20

Simplifying
a = -20
Subproblem 2
Set the factor '(2 + -1a)' equal to zero and attempt to solve:

Simplifying
2 + -1a = 0

Solving
2 + -1a = 0

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

Add '-2' to each side of the equation.
2 + -2 + -1a = 0 + -2

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

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

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

Simplifying
a = 2
Solution
a = {-20, 2}