Answer:
∴(x+5)(x+3) =x²+8x+15
Step-by-step explanation:
Standard form of a polynomial:
Standard of polynomial means that the terms ordered from biggest exponent of variable to lowest exponent of variable.
Example:

Given,
(x+5)(x+3)
=x(x+3)+5(x+3)
=x²+3x+5x+15
=x²+8x+15
∴(x+5)(x+3) =x²+8x+15
The degree of the polynomial is 2 and is a one variable polynomial.
Answer:
When f or g are equivalent to a number you are solving for x. For example b, d, e, f. In the equation g(x) =2x2-5 I assumed 2 was a typo. So, if it's incorrect, please use same steps and just adjust the solution.
Step-by-step explanation:

a)

b) 




c) 


d) 



e) 



f) 



It would go along with, "if I get better grades, then I study."
→ 
8 and 10 can both be divided by 2. So, 8 ÷ 2 is 4 and 10 ÷ 2 is 5.
Hope this helps :)