Algebraic Expressions(7th Grade > Mathematics ) Questions and answers for exam Preparation

7th Grade > Mathematics

ALGEBRAIC EXPRESSIONS MCQs

Total Questions : 116 | Page 5 of 12 pages

Question 41. Observe the pattern given below.

Observe The Pattern Given Below. What Is The General exp...

What is the general expression for this pattern?

n(n+1)2
n(n−1)2
n∗(n−1)
n2

Discuss Question

Answer: Option A. -> n(n+1)2
:
A

So the general expression for this pattern is

\frac{n (n + 1)}{2}

, where n is the next termand n= 1, 2, 3, 4....
[Alternatively, eliminate the options to figure out the correct answer. This is a good method while attending competitive exams where time plays a crucial role.]

Question 42. What should be the value of a, if the value of

2 x^{2} + 6 a - 5 x + 10

25

, when x = 1?

6
3
-3
-6

Discuss Question

Answer: Option B. -> 3
:
B

G i v e n, 2 x^{2} + 6 a - 5 x + 10 = 25

Substituting the value of x = 1 in the above equation, we get,

2 (1)^{2} + 6 a - 5 (1) + 10 = 25

\Rightarrow

2 + 6a - 5 + 10 = 25

\Rightarrow

6a + 7 = 25

\Rightarrow

6a = 25 - 7 = 18

\Rightarrow

a = 3

Question 43. What is the coefficient of term

x y^{3}

in the expression

5 x^{3} + 10 x y^{3}

10x
10
-10
-1

Discuss Question

Answer: Option B. -> 10
:
B
The coefficient of term

x y^{3}

in the expression

5 x^{3} + 10 x y^{3}

is10.
Acoefficient may be either a numerical factor (like 5, -3, 25...) or an algebraic factor (like

x, y, x^{3} y

...)or a product of two or more factors (like

3 x y, 5 x^{2} z

...)in a term of an algebraic expression.

∴

The coefficient of

x y^{3}

in the expression

5 x^{3} + 10 x y^{3}

is 10

Question 44.

5 a b^{3} + 22 a b c + 10 b c

is a ____________.

monomial
binomial
trinomial
term

Discuss Question

Answer: Option C. -> trinomial
:
C
A trinomial is defined as a polynomial which contains threeunlike terms. The expression

5 a b^{3} + 22 a b c + 10 b c

has three unlike terms andhence, it is a trinomial.

Question 45.

2 + 3 x

is an algebraic expression.

True
False
trinomial
term

Discuss Question

Answer: Option A. -> True
:
A
Analgebraic expressionis a mathematical phrase thatcontains numbers, variables (represented by lower case letters of the English alphabet) and operators (such as addition, subtraction, multiplication and division).
Here are some examples of algebraic expressions:

a + 1,

a - b,

3 x,

\frac{4}{3},

etc.
Hence,

2 + 3 x

is an algebraic expression.

Question 46. On subtracting

(x + a)

from

(4 x + 3 a)

, the result obtained is_____.

3x+2a
9x+6a
11x+2a
3x+7a

Discuss Question

Answer: Option A. -> 3x+2a
:
A
Arrange the polynomials with like terms one below the other. Change the sign of each term to be subtracted and then combine the like terms.

\begin{matrix} 4 x + 3 a x + a (-) (-) 3 x + 2 a \end{matrix}

(4 x + 3 a) - (x + a) = 3 x + 2 a

Question 47. Perimeter of a square plot with side 2

x

is 40 units. Find the length of the side of the square plot.

5 units
16 units
10 units
20 units

Discuss Question

Answer: Option C. -> 10 units
:
C
Perimeter of square = 40 units

4 \times

side = 40

4 \times 2 x

= 40

8 x

= 40
So,

x

= 5 units.
So,the length of each sideis

5 \times 2

= 10 units.

Question 48. The coefficient of xy in the expression '12xy + 6' is ___

Discuss Question

:
In the expression'12xy + 6', 'xy' is the variable part and it is multiplied to a constant part, which is called co-efficient of the variable.
In this case the coefficient of xy is 12.

Question 49.

2 x

and

(\frac{- 1}{2})

are ___ of the algebraic expression

(2 x - \frac{1}{2})

Discuss Question

:
The 'term' of an algebraic expressionis either a single number or variable, or number and variables multiplied together.
When such terms are added, it forms an algebraic expression.
So,