Answer:
Marc's age is 12
Step-by-step explanation:
Let
x ----> Marc's age
y ---> Tony's age
z ---> Ben's age
we know that
the sum of their ages is 40
so
-----> equation A
Marc is half as old as Tony
so
----> equation B
Marc is three times as old as Ben
so

----> equation C
substitute equation B and equation C in equation A

solve for x


therefore
Marc's age is 12
i believe it is 645, 500 !
Answer: c < 19
Step-by-step explanation:
Answer:
y=3x^2
Step-by-step explanation:
edge