Question

If 4x + 7y = 13 & 5x + 2y=5
then find x+y
(linear eq in two variables)​

Answer 1

question

4x + 7y = 13 ....... (1)

5x + 2y = 5 ..........(2)

to find

x + y = ?

as we know that

4x + 7y = 13 .... x 2

5x + 2y = 5 ...... x 7

multiply equation (1) by 2

multiply equation (2) by 7

8x + 14y = 26

35x + 14y = 35

- - -

- 27x = - 9

x = 1/3

put x = 1/3 in equation (2)

5/3 + 2y = 5

2y = 5 - 5/3

2y = 15 - 5/3

2y = 10/3

y = 5/3

value of x + y

1/3 + 5/3

6/3 = 2