Write four solutions for each of the following equations: 

(i) 2x + y = 7  (ii) πx + y = 9  (iii) x = 4y

(i) 2x + y = 7

For x = 0,  2(0) + y = 7 ⇒ y = 7

For x =1,  2(1) + y = 7 ⇒ y = 7 – 2 ⇒ y = 5

For x = 2, 2(2) + y =7y = 7 – 4 ⇒ y = 3

For, x = 3, 2(3) + y = 7y = 7 – 6 ⇒ y = 1

Therefore, the four solutions of the given equation are (0,7), (1,5), (2, 3) and (3,1)