Class IX, CBSE Guide NCERT Solutions
Linear Equations in Two Variables
NCERT Solutions of Class 9 Mathematics Exercise 4.1
Question.1: The cost of a note book is twice the cost of a pen. Write a linear equation in two variables to represent this statement.
(Take the cost of a note book Rs x and that of a pen Rs y)
Cost of cost of a note book Rs x and cost of a pen Rs x.
By given condition, x = 2y
⇒ x - 2y = 0 is the required linear equation.
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