40=s(s-3)

Solution for 40=s(s-3) equation:

Simplifying
40 = s(s + -3)

Reorder the terms:
40 = s(-3 + s)
40 = (-3 * s + s * s)
40 = (-3s + s2)

Solving
40 = -3s + s2

Solving for variable 's'.

Reorder the terms:
40 + 3s + -1s2 = -3s + 3s + s2 + -1s2

Combine like terms: -3s + 3s = 0
40 + 3s + -1s2 = 0 + s2 + -1s2
40 + 3s + -1s2 = s2 + -1s2

Combine like terms: s2 + -1s2 = 0
40 + 3s + -1s2 = 0

Factor a trinomial.
(8 + -1s)(5 + s) = 0

Subproblem 1
Set the factor '(8 + -1s)' equal to zero and attempt to solve:

Simplifying
8 + -1s = 0

Solving
8 + -1s = 0

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

Add '-8' to each side of the equation.
8 + -8 + -1s = 0 + -8

Combine like terms: 8 + -8 = 0
0 + -1s = 0 + -8
-1s = 0 + -8

Combine like terms: 0 + -8 = -8
-1s = -8

Divide each side by '-1'.
s = 8

Simplifying
s = 8
Subproblem 2
Set the factor '(5 + s)' equal to zero and attempt to solve:

Simplifying
5 + s = 0

Solving
5 + s = 0

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

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

Combine like terms: 5 + -5 = 0
0 + s = 0 + -5
s = 0 + -5

Combine like terms: 0 + -5 = -5
s = -5

Simplifying
s = -5
Solution
s = {8, -5}