Question

3x+4y=32,5x-4y=64.find the (x-y)and (x+y)​

Answer 1

(x - y) = 13 ; (x + y) = 11

Step-by-step explanation:

⇒ 3x + 4y = 32 ---(1)

⇒ 5x - 4y = 64 ---(2)

On adding (1) and (2), we get:

⇒ 3x + 4y + 5x - 4y = 32 + 64

⇒ 8x = 96

⇒ x = 12

On substituting the value of x in (1), we get: (We can substitute on either equation. Anyways, the value of y will be the same.)

⇒ 3(12) + 4y = 32

⇒ 3(3) + y = 8

⇒ 9 + y = 8

⇒ y = -1

Now, according to the question, we need to find the value of (x - y) and (x + y).

1) (x - y) = (12 - (-1))

  (x - y) = 13

2) (x + y) = (12 - 1)

   (x + y) = 11

The above method that we have used to find x and y is called as the elimination method.