Question

If 8x – 7y = 7 and 7x – 8y = 4, then what is the value of x + y ?​

Answer 1

Step-by-step explanation:

8x - 7y = 7 (A)7x + 8y = 8 (B)

7*(A): 56x - 49y = 49

8*(B): 56x + 64y = 64

8*(B)-7*(A): (64+49)*y = 64-49

=> 113y = 15

=> y = 15/113