Punjab State Board PSEB 9th Class Maths Book Solutions Chapter 4 Linear Equations in Two Variables Ex 4.1 Textbook Exercise Questions and Answers.
PSEB Solutions for Class 9 Maths Chapter 4 Linear Equations in Two Variables Ex 4.1
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 and that of a pen to be ₹ y.)
Answer:
Let the cost of a notebook be ₹ x and the cost of a pen be ₹ y.
Then, according to the given data, the cost of a notebook is twice the cost of a pen.
∴ x = 2y
Thus, x = 2y, i.e., x – 2y = 0 is the required linear equation in two variables.
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 = 9.3\(\overline{5}\)
Answer:
2x + 3y = 9.3\(\overline{5}\)
∴ 2x + 3y – 9.3\(\overline{5}\) = 0
Here, a = 2, b = 3 and c = – 9.3\(\overline{5}\).
(ii) x – \(\frac{y}{5}\) – 10 = 0
Answer:
x – \(\frac{y}{5}\) – 10 = 0
∴x – \(\frac{1}{5}\)y – 10 = 0
Here, a = 1, b = – \(\frac{1}{5}\) and c = – 10.
(iii) – 2x + 3y = 6
Answer:
– 2x + 3y = 6
∴ – 2x + 3y – 6 = 0
Here, a = 1, b = – 3 and c = – 6.
(iv) x = 3y
Answer:
x = 3y
∴ x – 3y + 0 = 0
Here, a = 1, b = – 3 and c = 0.
(v) 2x = – 5y
Answer:
2x = – 5y
∴ 2x + 5y + 0 = 0
Here, a = 2, b = 5 and c = 0
(vi) 3x + 2 = 0
Answer:
3x + 2 = 0
∴ 3x + oy – 2 = 0
Here, a = 3, b = 1 and c = – 2
(vii) y – 2 = 0
Answer:
y – 2 = 0
∴ 0x + y – 2= 0
Here a = 0, b = 1 and c = – 2
(viii) 5 = 2x
Answer:
5 = 2x
∴ 5 – 2x = 0
∴ – 2x + 0y + 5 = 0
Here a = – 2, b = 0, c = 5