Answer:
50
Step-by-step explanation:
3x = 25 - 5y
-100 < 5y < 50
-50 < -5y < 100
-25 < 25 - 5y < 125
-8.333 < x < 41.667
41+8+1 = 50
Is this the full question that is stated?
If f(1) =5-2(1)
F(2)=5-2(2)
This is a word problem signifying an algebraic expression.
Translating this to mathematics:

add 4 to both sides.
divide 16 to both sides.
this is:
Answer:
25
Step-by-step explanation:
he got an 80 so if that was his grade by answering 20 questions right then the correct answer would be 25 questions