Answer:
n = 5
n = 8
Step-by-step explanation:
n^2 - 13n = -40
Equate everything to zero
n^2 - 13n + 40 = 0
Factorise
(n - 5)(n - 8) = 0
Either
n - 5 = 0
Add 5 to both sides
n - 5 + 5 = 0 + 5
n = 5
Or
n - 8 = 0
Add 8 to both sides
n - 8 + 8 = 0 + 8
n = 8
n = 5 or
n = 8
It has two real solutions
