Ineed with direct variation equations

4)
a) you got it correct
b) y = 70x
c) Yes
d) f(6) = 70(6) = 420
e) f(x) = 210
    70x = 210
        x = 210/70
        x = 3
f) continuous
g) 
Domain: The set of all possible input values (commonly the "x" variable), which produce a valid output from a particular function.
 (-∞ , ∞)

Range: The range is the set of all possible output values (commonly the variable y, or sometimes expressed as f(x)f(x)), which result from using a particular function.
(-∞ , ∞)

5)
a) y = -5x
b) Yes, go thru (0,0)
and Yes, constant rate is -5
c) Yes
d)
f(11) = -5(11) = -55
e)f(x) = -45
-5x = -45
    x = 9

The total would be 40.53