NCERT Solutions
Class 9 - Mathematics - Chapter 4: LINEAR EQUATIONS IN TWO VARIABLES - EXERCISE 4.2
Question 3

Question. 3

Check which of the following are solutions of the equation \(x - 2y = 4\) and which are not:

(i) (0, 2)
(ii) (2, 0)
(iii) (4, 0)
(iv) \((\sqrt{2}, 4\sqrt{2})\)
(v) (1, 1)

Answer:

(i) No

(ii) No

(iii) Yes

(iv) No

(v) No

Detailed Answer with Explanation:

Test each ordered pair \((x, y)\) by substituting into \(x - 2y = 4\). If the left-hand side equals 4, it is a solution.

(i) \(0 - 2(2) = -4\) ≠ 4, so not a solution.

(ii) \(2 - 2(0) = 2\) ≠ 4, so not a solution.

(iii) \(4 - 2(0) = 4\) matches 4, so this is a solution.

(iv) \(\sqrt{2} - 2(4\sqrt{2}) = \sqrt{2} - 8\sqrt{2} = -7\sqrt{2}\), not 4, so not a solution.

(v) \(1 - 2(1) = -1\) ≠ 4, so not a solution.

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