Exercise 3.1 - Chapter 3 Algebra Term 1 7th Maths Guide Samacheer Kalvi Solutions - SaraNextGen [2024-2025]

Updated By SaraNextGen

On April 24, 2024, 11:35 AM

Ex $3.1$
Question $1 .$
Fill in the blanks
(i) The variable in the expression $16 x-7$ is
(ii) The constant term of the expression $2 y-6$ is
(iii) In the expression $25 \mathrm{~m}+14 \mathrm{M}$, the type of the terms are ___ terms
(iv) The number of terms in the expression $3 \mathrm{ab}+4 \mathrm{c}-9$ is Hint: Terms are $3 \mathrm{ab}, 4 \mathrm{c}-9$.
(v) The numerical co-efficient of the term -xy is
Hint: $-x, y=(-1) x y$.
Solution:
(i) $x$
(ii) $-6$
(iii) unlike
(iv) three
(v) $-1$

Question 2 .
Say true or False
(i) $x+(-x)=0$.
(ii) The co-efficient of ab in the term 15 abc is 15 .
Hint: Coefficient of $a b$ is $15 c$
(iii) $2 \mathrm{pq}$ and $-7 \mathrm{qp}$ are like terms.
(iv) When $y=-1$, the value of the expression $2 y-1$ is 3 .
Hint: $2(-1)-1=-2-1=-3$
Solution:
(i) True
(ii) False
(iii) True
(iv) False

Question $3 .$
Fing the numerical co-efficient of each of the following terms: $-3 y x, 12 k, y, 121 b c,-x, 9 p q, 2 a b$. Solution:
(i) Numerical co-efficient of-3yx is $-3$
(ii) Numerical co-efficient of $12 \mathrm{k}$ is 12
(iii) Numerical coefficient of y is 1
(iv) Numerical co-efficient of $1216 \mathrm{c}$ is 121
(v) Numerical co-efficient of $-x$ is $-1$
(vi) Numerical co-efficient of 9pq is 9
(vii) Numerical co-efficient of $2 \mathrm{ab}$ is 2

Question $4 .$
Write the variables, constants and terms of the following expressions,
(i) $18+\mathrm{x}-\mathrm{y}$
(ii) $7 \mathrm{p}-4 \mathrm{q}+5$
(iii) $29 \mathrm{x}+13 \mathrm{y}$
(iv) $b+2$
Solution:

Question 5.

Identify the like terms among the following 7x, 5y, -8x, 12y, 6z, z, -12x, -9y, 11 z

Solution

Question 6 .
If $x=2$ andy $=3$, then find the value of the following expressions,
(i) $2 x-3 y$
(ii) $x+y$
(iii) $4 \mathrm{y}-\mathrm{x}$
(iv) $x+1-y$
Solution:
Given $x=2 ; y=3$.
(i) $2 \mathrm{x}-3 \mathrm{y}=2(2)-3(3)=4-9$
$=4+($ Additive inverse of 9$)$
$=4+(-9)=-5$
(ii) $x+y=2+3=5$
(iii) $4 \mathrm{y}-\mathrm{x}=4(3)-2=12-2=10$
(iv) $x+1-y=2+1-3=3-3=0$

Objective Type Questions
Question $1 .$
An algebraic statement which is equivalent to the verbal statement "Three times the sum of ' $x$ ' and ' $\mathrm{y}$ ' is
(i) $3(x+y)$
(ii) $3+x+y$
(iii) $3 x+y$
(iv) $3+\mathrm{xy}$
Solution:
(i) $3[(x+y)]$

Question $2 .$
The numerical co-efficient of $-7 \mathrm{mn}$ is
(i) 7
(ii) $-7$
(iii) $\mathrm{p}$
(iv) $-\mathrm{p}$
Solution:
(ii) $-7$

Question $3 .$
Choose the pair of like terms
(i) $7 \mathrm{p}, 7 \mathrm{x}$
(ii) $7 \mathrm{r}, 7 \mathrm{x}$
(iii) $-4 x, 4$
(iv) $-4 x, 7 x$
Solution:
(iv) $-4 \mathrm{x}, 7 \mathrm{x}$
 

Question $4 .$
The value of $7 \mathrm{a}-4 \mathrm{~b}$ when $\mathrm{a}=3, \mathrm{~b}=2$ is
(i) 21
(ii) 13
(iii) 8
(iv) 32
Solution:
(ii) 13
Hint: $7(3)-4(2)=21-8=13$