**NCERT SOLUTIONS CLASS 9 MATHEMATICS**

**Exercise 4.1**

**Q.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 x and that of a pen to be y).

**Q.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: