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

Exercise 13 B

---

Expand the following :

---

Q1 | Ex-13B | Class-8 | Composite mathematics | Algebric Identities | Schand Solution | myhelper

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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

OPEN IN YOUTUBE

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 :

---