 # Linear equations in two Variables Chapter 4 Exercise 4.1

In this page we have NCERT solutions for class 9 maths chapter 4 Exercise 4.1 on page 68. Hope you like them and do not forget to like , social share and comment at the end of the page.
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 cost of notebook and a pen be x and y respectively.
Cost of note book = 2 cost of pen
$x = 2y$
$x - 2 y = 0$

Question 2
Express the following linear equations in the form ax + by + c = 0 and indicate the values of a, b, c in each case:
(i) $2x+3y=9.3\bar{5}$
(ii) $x- \frac {y}{5}-10=0$
(iii) $-2x + 3 y = 6$
(iv) $x = 3y$
(v) $2x = - 5y$
(vi) $3x + 2 = 0$
(vii) $y - 2 = 0$
(viii) $5 = 2x$
Solution
(i) $2x+3y=9.3\bar{5}$
=> $2x+3y-9.3\bar{5} =0$
Comparing this equation with $ax + by + c = 0$,
a=2 ,b=3 $c=-9.3\bar{5}$.

(ii) $x- \frac {y}{5}-10=0$
Comparing this equation with $ax + by + c = 0$,
a = 1, b =-1/5,c = -10

(iii) $-2x + 3 y = 6$
=> $-2x + 3 y - 6 = 0$
Comparing this equation with $ax + by + c = 0$,
a = -2, b = 3, c = -6
(iv)$x = 3y$
=> $x - 3y + 0 = 0$
Comparing this equation with $ax + by + c = 0$,
a = 1, b = -3, c = 0
(v) $2x = - 5y$
=> $2x + 5y + 0= 0$
Comparing this equation with $ax + by + c = 0$,
a = 2, b = 5, c = 0
(vi) $3x + 2 = 0$
=> $3x + 0.y + 2 = 0$
Comparing this equation with $ax + by + c = 0$,
a = 3, b = 0, c = 2
(vii) $y - 2 = 0$
=> y - 2 = 0
Comparing this equation with $ax + by + c = 0$,
a = 0, b = 1, c = -2
(vii) $5 = 2x$
=> $- 2x + 5 = 0$
Comparing this equation with $ax + by + c = 0$,
a = -2, b = 0, c = 5

## Summary

1. NCERT solutions for class 9 maths chapter 4 Exercise 4.1 has been prepared by Expert with utmost care. If you find any mistake.Please do provide feedback on mail. You can download the solutions as PDF in the below Link also
2. This chapter 4 has total 4 Exercise 4.1 ,4.2,4.3 and 4.4. This is the First exercise in the chapter.You can explore previous exercise of this chapter by clicking the link below 