Page 84 - Maths Skills - 8

82 Maths

B. Fill in the Blanks marked as Assertion (A) and Reason (R). Mark your
answer as per the codes provided below:
1. Expression 2p + 7p is a _____________ . (a) Both A and R are true and R is the correct
2. Expression 2p + 2q + 8p is a ____________ . explanation of A.

3. The equivalent of a + 2ab + b is equal to (b) Both A and R are true but R is not the correct
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2
_____________ . explanation of A.
4. The equivalent of (a + b)(a – b)is equal to (c) A is true but R is false.
_____________ .
(d) A is false but R is true.
C. Write ‘T’ for true and ‘F’ for false statements Q. 1. Assertion (A): 6 is the degree of polynomial
obtained by multiplying (x + 6)
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1. 4p q + 3qp + 5pq is a trinomial.
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2
2
and (x + x + 6x + 9x + 15).
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3
2
1
2. 3a b + 5ab – ab is a polynomial. Reason (R): The highest power of the variables
2
–2
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3. The value of 3a(a – 3) is 3a – 9a. is called the degree of the polynomial.
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Q. 2. Assertion (A): 5xy (9xy + 6xy ) = 45x y + 30x y
2 2
2 3
2
4. The value of 14b (b – 1) is 14b – 1.
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Reason (R): To multiply a monomial by a
D. Case Study Based Questions binomial then we can use distributive property.
A dealer buys a rectangular plot for constructing a
godown whose length is 2x, breadth is (3x–y) and its SUBJECTIVE TYPE QUESTIONS
height is (x –2x + 4). All measurements are considered F. Solve the following word problems
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in meter. After construction of the godown, he plans 1. In 2021, a school enrolled 5x + 3x + 7 students.
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to tile the floor of godown using tiles each of side Out of these, 3x – 4x + 3 students were girls.
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4x m. How many boys were enrolled?
Answer the following questions on the basis of the
above data. 2. Multiply 5 yz, 7 x and (– 3xz ), and then
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2
2
9 10
1. Find out the volume of godown. 1 1 1
2. How many such tiles will the merchant have verify the result for x = , y = and z = .
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2
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to buy? 3. If x + y = 12 and xy = 3, find the value of (x + y ).
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2
3. If the cost of one tile is ` (5x + 3) then how much

will it cost the merchant to get the tiles installed? 4. If x 1 = 8, find the value of x 1 and

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2
x x
E. Assertion-Reason Based Questions 1
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4
Directions for Questions 1 to 2: In each of the x x .

questions given below, there are two statements

5. If x 1 = 2, find the value of x 1 .

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2

x x
HOTS
1. Using the identity (a + b + c) = a + b + c + 2ab + 2bc + 2ca, evaluate the following:
2
2
2
2
(i) (x – 2y + 3z) (ii) (2x – 5y + 7z) (iii) (4p – 3q – 2r) 2
2
2
(iv) 5a 1 b 3 c 2 (v) (–2x + y – 8z) 2 (vi)  −− 1 m − 6   2
l


2 4  2 