Suppose a new MyPhone cellphone costs $ 700, and depreciates in value by $ 35 per month. A new Cyborg phone costs $ 600, and depreciates in value by 30 per month.
a) Let $M(x)$ be the value of a MyPhone $x$ months after it was purchased, and let $C(x)$ be the value of a Cyborg $x$ months after it was purchased. Write formulas for $M(x)$ and $C(x)$.
$M(x)=$
$C(x)=$

b) If Carrie and Miranda buy phones at the same time, Carrie buying the Cyborg and Miranda buying the MyPhone, when will their phones have the same value? If you get a decimal answer, please round your answer to the next whole month (round up).
$x=$ months

c) After how many months are each of the phones worth nothing? If you get a decimal answer, please round your answer to the next whole month (round up).
The MyPhone is worth nothing after months.
The Cyborg is worth nothing after months.

Hint: