NCERT Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1

NCERT Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1

NCERT Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1

NCERT Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1 are the part of NCERT Solutions for Class 9 Maths. Here you can find the NCERT Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1.

Ex 4.1 Class 9 Maths Question 1.
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 a notebook be Rs. X and the cost of a pen be Rs. Y.
According to the question, we have
[The cost of a notebook] = 2 × [The cost of a pen]
x = 2 × y

Or, x = 2y
Or, x – 2y = 0
Thus, the required linear equation is x – 2y = 0.

Ex 4.1 Class 9 Maths Question 2.
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 = 9.35¯
(ii) x – y/5 – 10 = 0
(iii) –2x + 3y = 6
(iv) x = 3y
(v) 2x = –5y
(vi) 3x + 2 = 0
(vii) y – 2 = 0
(viii) 5 = 2x

Solution:
(i) The given linear equation is, 2x + 3y = 9.35¯
(2)x + (3)y + (-9.35¯) = 0
On comparing the above equation with ax + bx + c = 0, we have
a = 2, b = 3 and c = –9.35¯

(ii) The given linear equation is, x – y/5 – 10 = 0
x + (-1/5)y + (-10) = 0
On comparing the above equation with ax + by + c = 0, we have
a = 1, b = –1/5 and c = -10

(iii) The given linear equation is, -2x + 3y = 6
-2x + 3y – 6 = 0
(-2)x + (3)y + (-6) = 0
On comparing the above equation with ax + by + c – 0, we have
a = –2, b = 3 and c = –6

(iv) The given linear equation is, x = 3y
x – 3y = 0
(1)x + (-3)y + 0 = 0
On comparing the above equation with ax + by + c = 0, we have
a = 1, b = -3 and c = 0.

(v) The given linear equation is, 2x = –5y
2x + 5y = 0
(2)x + (5)y + 0 = 0
On comparing the above equation with ax + by + c = 0, we have
a = 2, b = 5 and c = 0.

(vi) The given linear equation is, 3x + 2 = 0
3x + 2 + 0y = 0
(3)x + (0)y + (2) = 0
On comparing the above equation with ax + by + c = 0 , we have
a = 3, b = 0 and c = 2.

(vii) The given linear equation is, y – 2 = 0
(0)x + (1)y + (-2) = 0
On comparing the above equation with ax + by + c = 0, we have
a = 0, b = 1 and c = –2.

(viii) The given linear equation is, 5 = 2x
5 – 2x = 0
-2x + 0y + 5 = 0
(-2)x + (0)y + (5) = 0
On comparing the above equation with ax + by + c = 0, we have
a = –2, b = 0 and c = 5.

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