Question

Example 2: Romila went to a stationery shop and purchased 2 pencils and 3 erasers
for 9. Her friend Sonali saw the new variety of pencils and erasers with Romila, and
she also bought 4 pencils and 6 erasers of the same kind for 18. Represent this
situation algebraically and graphically.​

Answer 1

Answer:

Let the cost of pencil be x.

& let the cost of eraser be y.

Romila purchased 2 pencils & 3 erasers for RS 9

2 x (cost of pencil)+3 x (cost of eraser)=9

2x+3y=9

2x+3y-9=0..............(1)

Also,

sonali purchased 4 pencils and 6 erasers for RS 18

4 x (cost of pencil)+6 x (cost of eraser) =18

4x+6y=18

4x+6y-18=0..............(2)

Now plotting equations :

2x+3y-9=0............. (1)

4x+6y-18=0.............(2)

solving (1)

solving (1)2x+3y-9=0

solving (1)2x+3y-9=03y=9-2x

solving (1)2x+3y-9=03y=9-2xy=9-2x/3

Let x=0 Let x=3

y=9-0/3 y=9-2(3)/3

y=9/3 y=9-6/3

y=3 y=3/3 =1

so x=0,y=3 is a solution. so x=3,y=1 is a sol..

I. e., (0,3) is a solution. I. e.,(3,1) us a sol..

solving (2)

4x+6y -18 =0

6y= 18-4x

y=18-4x/6

putting x=