Somebody help me?
I’ve been stuck on the same question for days now

7

Step-by-step explanation:

You've said that both triangle are equal.

This means, both are in proportion

Let the unknown side be x

4 : 5 : x = 36 : 45 : 63

Divide LHS by 9

4 : 5 : x = 4 : 5 : 7

Since you may see x and 7 are same. So, the missing side is 7.

(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