Please help with this

= n² + 4n ; n = 11

Step-by-step explanation:

= [2 + (n - 1)d]

~~~~~~~~~

= 5

d = 7 - 5 = 2

= [ 2(5) + 2(n - 1)] = ( 8 + 2n ) = 4n + n²

= n² + 4n

n² + 4n = 165

n² + 4n - 165 = 0

(n + 15)(n - 11) = 0 ( n ≥ 0 ) ⇒ n = 11

(f - g)(x) = 5x^3 - 3

step-by-step explanation:

rearrange these functions vertically, with like terms in separate columns:

f(x) = 5x^3 - 2

g(x) =         +1

now subtract, column by column:

(f - g)(x) = 5x^3 - 3