Question

If equation one is mutiplied by 2 and then the equations are added the result is 2x+y=3 X-2y=-1

Answer 1

Question:

2x + y = 3, x - 2y = –1.

If equation one is multiplied by 2 and then the equations are added, the result is _____.

(A) 3x = 2

(B) 3x = 5

(C) 5x = 5

Answer:

Option C:

5x = 5

Solution:

Given equations are

2x + y = 3 – – – – (1)

x – 2y = –1 – – – – (2)

Let us first multiply equation (1) by 2, we get

(1) × 2 ⇒ 4x + 2y = 6 – – – – (3)

Now, add equation (3) to equation (2).

⇒ x – 2y + 4x + 2y = –1 + 6

Combine like terms together.

⇒  x + 4x – 2y  + 2y = –1 + 6

⇒ 5x = 5

So, if equation one is multiplied by 2 and then the equations are added, the result is 5x = 5.