Write four solutions for each of the following equations:

(1) 2x + y = 7 ⇒ y = 7 – 2x
Putting x = 0, we have, y = 7 – 2 x 0 = 7, therefore, (0, 7) is a solution of the equation.
Putting x = 1, we have, y = 7 – 2 x 1 = 5, therefore, (1, 5) is a solution of the equation.
Putting x = 2, we have, y = 7 – 2 x 2 = 3, therefore, (2, 3) is a solution of the equation
Putting x = 3, we have, y = 7 – 2 x 3 = 1, therefore, (3, 1) is a solution of the equation.
Hence, (0, 7), (1, 5), (2, 3) and (3, 1) are the four solutions of the equation 2x + y = 7.

(ii) πx + y = 9 ⇒ y = 9 – πx
Putting x = 0, we have, y = 9 – π × 0 = 9, therefore, (0, 9) is a solution of the equation.
Putting x = 1, we have, y = 9 – π × 1 = 9 – π, therefore, (1, 9 – π) is a solution of the equation.
Putting x = 2, we have, y = 9 – π × 2 = 9 – 27, therefore, (2, 9- 2π) is a solution of the equation.
Putting x = 3, we have, y = 9 – πx 3 = 9 – 3π, therefore, (3, 9 – 3π) is a solution of the equation.
Hence, (0, 9), (1, 9 – π), (2, 9 – 2π) and (3, 9 -3π) are the four solutions of the equation πx + y = 9.

(iii) x = 4y
Putting y = 0, we have, x = 4 × 0 = 0, therefore, (0, 0) is a solution of the equation.
Putting y = 1, we have, x = 4 × 1 = 4, therefore, (4, 1) is a solution of the equation.
Putting y = 2, we have, x = 4 × 2 = 8, therefore, (8, 2) is a solution of the equation.
Putting y = 3, we have, x = 4 × 3 = 12, therefore, (12, 3) is a solution of the equation.
Hence, (0, 0), (4, 1), (8, 2) and (12, 3) are the four solutions of the equation x = 4y.