Answer:
Rate of change = -30
Initial value = 400
Step-by-step explanation:
Write the equation of the linear function representing this situation. Let
x = number of weeks Gandalf is spending money
y = amount of quibbles left in his account.
Gandalf has 400 quibbles in his account. This means, [tex]b=400[/tex] is the initial value of quibbles Gandalf had in his account
He spends 30 quibbles each week, this means, that he spends 30x quibbles in x weeks and the amount left in his account is
[tex]y=400-30x[/tex]
Therefore, the slope is [tex]-30[/tex] and this is the rate of change (negative because the amount of money in his account decreases each week)