Tag: Exercise 4.1 Chapter 4 NCERT Class 9th Maths Solutions Linear Equations in Two Variables

Q1. The cost of a notebook is twice the cost of a pen.
(Take the cost of a notebook to be ₹x and that of a pen to be ₹y.)

Answer 1.
Equation: ${\displaystyle x=2y\mathrm{}}$
(Or equivalently $x-2y=0$)

Q2. Express the following linear equations in the form $ax+by+c=0$ and indicate $a,b,c$ in each case:

(i) $2x+3y=9.35$
Rewrite: $2x+3y-9.35=0$
So $a=2,b=3,c=-9.35$

(ii) $x-5y-10=0$
(Already in required form.)
So $a=1,b=-5,c=-10$

(iii) $-2x+3y=6$
Rewrite: $-2x+3y-6=0$
So $a=-2,b=3,c=-6$

(iv) $x=3y$
Rewrite: $x-3y=0$
So $a=1,b=-3,c=0$

(v) $2x=-5y$
Rewrite: $2x+5y=0$
So $a=2,b=5,c=0$

(vi) $3x+2=0$
Rewrite: $3x+0\cdot y+2=0$
So $a=3,b=0,c=2$

(vii) $y-2=0$
Rewrite: $0\cdot x+y-2=0$
So $a=0,b=1,c=-2$

(viii) $5=2x$
Rewrite: $2x-5=0$ (i.e. $2x+0\cdot y-5=0$).
So $a=2,b=0,c=-5$