S.chand books class 8 maths solution chapter 13 Algebric Identities exercise 13 A

Exercise 13 A

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Multiply mentally and write only the products for each of the following .

Q1 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 1

(x+4)(x+2)

Sol :

x²+6x+8

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Q2 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 2

(a+1)(a+8)

Sol :

a²+9a+8

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Q3 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 3

(c+3)(c+2)

Sol :

c²+5c+6

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Q4 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 4

(b-2)(b-5)

Sol :

b²-7b+10

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Q5 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 5

(n-1)(n-6)

Sol :

n²-7n+6

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Q6 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 6

(3-x)(5-x)

Sol :

15-8x+x²

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Q7 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 7

(y-7)(y+3)

Sol :

y²-4y-21

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Q8 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 8

(m+3)(m-2)

Sol :

m²+m-6

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Q9 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 9

(x-4)(x+6)

Sol :

x²+2x-24

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Q10 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 10

(p+10)(p-9)

Sol :

p²+p-90

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Q11 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 11

(xy+6)(xy-5)

Sol :

x²y²+xy-30

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Question 12

(5-xy)(3+xy)

Sol :

15+2xy-x²y²

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Q13 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 13

(x²+3)(x²-8)

Sol :

x⁴-5x²-24

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Question 14

(4-x²)(10+x²)

Sol :

40-6x²-x⁴

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Question 15

(ab-13)(ab-4)

Sol :

a²b²-17ab+52

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Question 16

(2x+3)(3x+2)

Sol :

6x²+13x+6

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Question 17

(4x+7)(5x+6)

Sol :

20x²+59x+42

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Question 18

(7x+1)(x+3)

Sol :

7x²+22x+3

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Q19 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 19

(2a²+3b²)(2a²-5b²)

Sol :

4a⁴-4a²b²-15b⁴ 

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Q20 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | myhelper

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Question 20

(2x²-7y²)(3x²+8y²)

Sol :

6x⁴-5x²y²-56y²⁴

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Q21 | Ex-13A | Class-8 | Composite mathematics | Schand Solution | Chapter 13 | myhelper

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Question 21

Find by inspecting the coefficient of x in the following expansions

(i) (x+17)(x+2)

Sol :

(ii) (x+1)(3-x)

Sol :

(iii) (x-p)(x-q)

Sol :

(iv) (2+3x)(3-5x)

Sol :

(v) (5-x)(x+8)

Sol :

(vi) (px-1)(px-1)

Sol :