- The cost of a notebook is twice the cost of a pen. Write a linear equation in two variables to represent this statement.
(Take the cost of a notebook to be Rs x and that of a pen to be Rs y).
Solution:
Let the cost of the notebook be ‘x’ and the cost of the pen be ‘y’
Then by the given data, x = 2y
This can be written as x – 2y = 0
- Express the following linear equations in the form ax + by + c = 0 and indicate the values of a, b and c in each case:
(i) 2x + 3y = 9.3
Solution:
2x + 3y – 9.3 = 0
Therefore, a = 2 , b = 3 , c = – 35
(ii) x – y/5 – 10 = 0
Solution:
a = x ; b = – 1/5 ; c = -10
(iii) –2x + 3y = 6
-2x + 3y – 6 = 0
a = -2 ; b = 3 ; c = -6
(iv) x = 3y
x – 3y = 0
Thus, a = 1 ; b = -3 ; c = 0
(v) 2x = –5y
2x + 5y = 0
a = 2 and b = 5 , c = 0
(vi) 3x + 2 = 0
3x + 0.y + 2 = 0
a = 3 ; b = 0 ; c = 2
(vii) y – 2 = 0
0.x + y – 2 = 0
a = 0 ; b = 1 and c = -2
(viii) 5 = 2x
– 2x + 5 = 0
– 2x + 0.y + 5 = 0
Thus, a = -2 ; b = 0 and c = 5
1 thought on “Linear Equations in Two variables – Exercise 4.1 – Class IX”
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