Question

5x-7y=25 and 7x-5y=23 Then what is the value of x+y?​

Answer 1

Answer:

in first the x vaule is 5 and y value is 7

in second x value is 7 and y value is 5

Answer 2

The value of x + y = -1.

Step-by-step explanation:

We have,

5x - 7y = 25             ......(1)

and 7x - 5y = 23      ......(2)

To find,the value of x + y=?

Multiplying (1) by 5 and (2) by 7, we get

25x - 35y = 125             ......(3)

and 49x - 35y = 161        ......(4)

Subtracting (3) from (4), we get

- 24x = 36

⇒  $x=-\frac{36}{24}=-\dfrac{3}{2}$

Put $x=-\dfrac{3}{2}$ in (1), we get

$5(\dfrac{3}{2} )-7y=25$

⇒ $y=-\dfrac{5}{2}$

∴ x + y $=\dfrac{3}{2}-\dfrac{5}{2}=\dfrac{3-5}{2}=-1$

Hence, the value of x + y = -1.