Loading [MathJax]/jax/output/CommonHTML/jax.js

CLASS:- 9 EXERCISE:- 4.1 LINEAR EQUATIONS IN TWO VARIABLES ALL SOLUTION

CLASS :- 9, EX :- 4.1



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).

solution :

Let the cost of a notebook to be = ₹ x

Let the cost of a pen to be = ₹ y

According to the question,

Cost of a notebook = 2 × Cost of a pen

x=2×y

x=2y

x−2y=0

The cost of a notebook is twice the cost of a pen.

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=9.3ˉ5

(ii)  x-y5-10=0

(iii)  -2x+3y=6

(iv)  x=3y

(v)  2x=-5y

(vi)  3x+2=0

(vii)  y-2=0

(viii)  5=2x

solution :

(i)  2x+3y=9.3ˉ5

  2x+3y=9.3ˉ5 can be written as 2x+3y-9.3ˉ5=0

Now, comparing 2x+3y-9.3ˉ5=0 with ax+by+c=0

Here,

a=2

b=3

c=-9.3ˉ5

(ii)  x-y5-10=0

  x-y5-10=0 can be written as 1x-15y-10=0

Now, comparing 1x-15y-10=0 with ax+by+c=0

Here,

a=1

b=15

c=-10

(iii)  -2x+3y=6

  -2x+3y=6 can be written as -2x+3y-6=0

Now, comparing -2x+3y-6=0 with ax+by+c=0

Here,

a=-2

b=3

c=-6

(iv)  x=3y

  x=3y can be written as 1x-3y+0=0

Now, comparing 1x-3y+0=0 with ax+by+c=0

Here,

a=1

b=-3

c=0

(v)  2x=-5y

  2x=-5y can be written as 2x+5y+0=0

Now, comparing 2x+5y+0=0 with ax+by+c=0

Here,

a=2

b=5

c=0

(vi)  3x+2=0

  3x+2=0 can be written as 3x+0y+2=0

Now, comparing 3x+0y+2=0 with ax+by+c=0

Here,

a=3

b=0

c=2

(vii)  y-2=0

  y-2=0 can be written as 0x+1y-2=0

Now, comparing 0x+1y-2=0 with ax+by+c=0

Here,

a=0

b=1

c=-2

(viii)  5=2x

  5=2x can be written as -2x+0y+5=0

Now, comparing -2x+0y+5=0 with ax+by+c=0

Here,

a=-2

b=0

c=5



0 Comments