Exercise 13 B
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Q1 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution |
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Question 1
(i) (x+5)2
(ii) (3x+4)2
(iii) (3x+5y)2
(iv) (1+10mn)2
Sol :
Q2 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
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Question 2
(i) (7y-8)2
(ii) (p-2q)2
(iii) (5y-3z)2
(iv) (6a-11b)2
Sol :
Q3 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
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Question 3
(i) (a2+1)2
(ii) (3a2+b2)2
(iii) (xy-4z)2
(iv) (5a2-7b2)2
Sol :
Q4 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
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Question 4
(i) $\left(x+\dfrac{1}{x}\right)^2$
(ii) $\left(2y-\dfrac{1}{2y}\right)^2$
Sol :
Q5 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
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Question 5
(i) (1.5p+2q)2
(ii) $\left(5p-\dfrac{1}{4q}\right)^2$
(iii) (3.2d-5f)2
(iv) $\left(2x^2-\dfrac{1}{3x^2}\right)^2$
Sol :
Q6 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
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Question 6
Simplify :
(i) (x+3y)2+ (3x+y)2
(ii) (x-2y)2+ (2x-y)2
(iii) (2x+5y)2- (x+3y)2
Sol :
Q7 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 7
Without actual multiplication , find the square of
(i) 98
(ii) 1003
(iii) 999
(iv) 10.8
(v) 99.99
Sol :
Q8 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 8
Simplify :
(i) 7.61×7.61+2×7.61×2.39+2.39×2.39
(ii) 79.01×79.01+2×79.01×20.99+20.99×20.99
(iii) 0.768×0.768-2×0.768×0.568+0.568×0.568
Sol :
Q9 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 9
State which of the following expansions is a perfect square.
(i) 4m2+4m+1
(ii) 25q2-40q+16
(iii) a2-6ab-9b2
(iv) $4x^2-2+\dfrac{1}{4x^2}$
Sol :
Q10 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 10
What term should be added to each of the following expressions to make it
a perfect square ?
(i) 4a2+28a
(ii) 16+8y
(iii) a2-2a
(iv) 9-6x
Sol :
Q11 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 11
Find the missing term in the following perfect squares.
(i) 9m2-()+64n2
(ii) ()+48x+64
(iii) 25a2+120ab+()
(iv) ()-90xy+81y2
Sol :
Q12 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 12
Find the value of a2+b2 , when
(i) a+b=9 , ab=20
(ii) a-b=5 , ab=14
Sol :
Q13 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 13
Find the value of $x^2+\dfrac{1}{x^2}$ , when
(i) $x+\dfrac{1}{x}=3$
(ii) $x-\dfrac{1}{x}=11$
Sol :
Q14 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 14
Find the value of $x^4+\dfrac{1}{x^4}$ , when
(i) $x+\dfrac{1}{x}=3$
(ii) $x-\dfrac{1}{x}=4$
Sol :
Q15 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper
Question 15
Find the value of
(i) m-n , if m+n=7 , mn=12
(ii) l+m , if l-m=3 , lm=7
(iii) p2+q2 , if p-q=6 and p+q=14
(iv) 4ab, if a+b=9 and a-b=5
(v) 4cd(c2+d2) , if c+d=11 , c-d=1
Sol :
