Question

The cost of a notebook is rs 5 less than twice the cost of a pen.

a) write as linear equation in 2 variable
b)is (-1,2) a solution?

Answer 1

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,

`n=2p-5\\-1=2(2)-5\\-1=4-5\\-1=-1\\1=1`

Hence (-1,2) is a solution