Question

If 2x + y = 13 and 4x – y = 17, find the value of (x – y).

Answer 1

Given: 2x + y = 13 and 4x – y = 17.

Use elimination by adding the two equations.

Add: (2x + y) + (4x – y) = 13 + 17

⇒ 6x = 30

⇒ x = 5

Substitute x = 5 into 2x + y = 13

⇒ 2(5) + y = 13

⇒ 10 + y = 13

⇒ y = 3

Compute x – y = 5 – 3

= 2