Answer:
a) the equation is, n = 2p - 5
b) Yes, (-1,2) is a solution of n = 2p-5
Explanation:
The cost of a notebook is 5 less than twice the cost of a pen
let cost of notebook be n
and cost of pen be p
then we get the following relation,
(The cost of a notebook is 5 less than twice the cost of a pen)
n = 2p - 5
(2p = twice the cost of the pen)
b) Checking if (-1,2) is a solution,

Hence (-1,2) is a solution