Question

If 3x + 5y = 9 and 5x + 3y = 7, then what is the value of x + y ?
(A) 2
(B) 16
(C) 9
(D) 7
Answer:
(A) 2​

Answer 1

3x+5y=9-----(1)

5x+3y=7-----(2)

multiplying eq(1) by 5 & eq(2) by 3 we get

15x+25y=45

-15x ± 9y= - 21

_____________

16y=24

y= 24/16

= 3/2

[y= 3/2 ] and x= 9-5x3/2/3 = −1/2

Hence[x= 1/2 ]& [y= 3/2 ]

so x+y= 1/2+3/2 =2

answer is(A) 2 is correct

Answer 2

Step-by-step explanation:

3x+5y=9-----(1)

5x+3y=7-----(2)

multiplying eq(1) by 5 & eq(2) by 3 we get

15x+25y=45

-15x ± 9y= - 21

_____________

16y=24

y= 24/16

= 3/2

[y= 3/2 ] and x= 9-5x3/2/3 = −1/2

Hence[x= 1/2 ]& [y= 3/2 ]

so x+y= 1/2+3/2 =2

answer is(A) 2 is correct

Hope helps:-)