Question

Solve the following pair of linear equations for x and y algebraically:

x + 2y = 9 and y − 2x = 2

Answer 1

Given the pair of linear equations as,

⇒ x + 2y = 9     ...(i)

⇒ y − 2x = 2

⇒ −2x + y = 2    ...(ii)

Multiplying eqn (i) by 2 and adding to eqn (ii), we get

⇒ (−2x + y) + ( 2x + 4y) = 2 + 18

⇒ 5y = 20

⇒ y = 4

Putting in eqn (i),

⇒ x + 2(4) = 9

⇒ x = 9 − 8

⇒ x = 1

So, the required solution is x = 1 and y = 4