Answer:
y= 7^-t
Step-by-step explanation:
Equation for exponential decay:
An equation represents exponential decay if a term between 0 and 1 is elevated to the independent variable.
In this question:
First option 4 is elevated, so not exponential decay.
Second option:

, thus, the second option represents exponential decay.
Answer:
the original price of the cooker is £320 and David has been a deposit of 15% so find 15% of the original price and the deposit is £48
Without the graph it is impossible the find the value of K
Hope this helps. :D
(Please mark as brainliest thanks)