Question

find the value of x+y and x-y if 15x+17y =21 17x+15y=11​

Answer 1

Answer:

x+y=1

x-y=-5

simplify both the equations and find the value of y.

then substitute the value of y in any of the equation to get the value of x.

next find out x+y and x-y

Answer 2

Answer:

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

17x+15y=11--(ii)

adding

15x+17y+ 17x+15y=21 +1 1

=>32x +32 Y = 32

X +y=1

subtracting eqi) from ii)

we get,

17x+15y-15x-17y=11-21

2x-2y= -10

X-y=. -5