Question

If 15x+17y=21 and 17x+15 y=.find x+y​

Answer 1

Answer:

15x+17y=21 .....(1)

17x+15y=11 .....(2)

17×eqn(1)−15× eqn(2) gives

255x+289y−255x−225y=357−165

⇒64y=192

⇒y=

64

192

=3

Substitute the value of y=3 in (1) we get

15x+17×3=21

⇒15x=21−51=−30

∴x=

15

−30

=−2

Hence x=−2,y=3

And x+y=−2+3=1

Answer 2

Answer:

15x+17y=21 .....(1)

17x+15y=11 .....(2)

17×eqn(1)−15× eqn(2) gives

255x+289y−255x−225y=357−165

⇒64y=192

⇒y=

64

192

=3

Substitute the value of y=3 in (1) we get

15x+17×3=21

⇒15x=21−51=−30

∴x=

15

−30

=−2

Hence x=−2,y=3

And x+y=−2+3=1

follow me

and pls give the working also of the question u just solved of coordinate geometry