Question-Mathematics - Algebraic Expressions - Ask NCERT class 8 Algebraic Expressions and Identities with solution questions answer. All ncert questions Answers for class 8 subject Mathematics chapter Algebraic Expressions and Identities and topic Algebraic Expressions

**Question 1.** **Asked on :**21 November 2022:01:23:27 PM

Solve for x (in term of a and b):

a/x-b + b/x-a = 2, x≠ a,b

*-Added by Master Purushottam* See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

a(x-a) + b(x-b)

(x-b) (x-a) = 2

cross multiplying both the sides

a(x-a) + b(x-b) = 2[x^{2}-(a+b)x+ ab]

ax- a^{2 }+ bx -b^{2}_{ }= 2x^{2} -2(a+b)x + 2ab

2x^{2} -3(a+b)x + (a+b)^{2} = 0

2x^{2} -2(a+b)x -(a+b)x + (a+b)^{2} = 0

[2x- (a+b) ] [x-(a+b)] = 0

^{ }_{ }^{ } _{ }^{ }

x = a + b, a + b2

*-Answered by Master Purushottam* On 09 June 2022:10:46:59 AM

**Question 2.** **Asked on :**21 November 2022:01:09:57 PM

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

x

*-Answered by Shruti Srivastva * On 05 August 2020:05:57:19 PM

**Question 3.** **Asked on :**18 November 2022:04:11:33 PM

Prove that:

(x-y)^{3} = x^{3} - y^{3} - 3xy(x-y)

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(x-y)^{3 }= x^{3 }- y^{3 }- 3xy(x-y)

L.H.S: (x - y)^{3}

= (x - y) (x - y) (x - y)

= (x - y) (x^{2 }- 2xy + y^{2})

= x(x^{2 }- 2xy + y^{2}) - y (x^{2 }- 2xy + y^{2})

= x^{3}- 2x^{2}y + xy^{2} - x^{2}y + 2xy^{2} - y^{3}

= x^{3}- 3x^{2}y + 3xy^{2} - y^{3}

= x^{3}- 3xy(x - y) - y^{3}

= x^{3 }- y^{3 }- 3xy(x-y)

LHS = RHS

Hence Proved

*-Answered by Shruti Srivastva * On 05 August 2020:05:55:27 PM

**Question 4.** **Asked on :**18 November 2022:01:35:49 PM

Prove the identity (x+y)^{3} = x^{3 }+ y^{3} + 3xy(x+y)

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(x+y)

*-Answered by Shruti Srivastva * On 05 August 2020:05:54:00 PM

**Question 5.** **Asked on :**18 November 2022:01:28:51 PM

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(x+a)(x+b) = x^{2} + (a+b)x + ab

L.H.S = (x + a) (x + b)

= x(x + b) + a(x + b)

= x^{2 }+ xb + xa + ab

= x^{2 }+ (a + b)x + ab

L.H.S = R.H.S

Hence Proved

*-Answered by Shruti Srivastva * On 05 August 2020:05:50:31 PM

**Question 6.** **Asked on :**18 November 2022:01:23:25 PM

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(a-b)^{2 }= a^{2 }- 2ab + b^{2}

L.H.S = (a - b)^{2}= (a - b) (a - b)

= a(a - b) - b(a - b)

= a^{2} - ab - ab + b^{2}

= a^{2} - 2ab + b^{2}

^{L.H.S = R.H.S }

^{Proved }

*-Answered by Shruti Srivastva * On 05 August 2020:05:48:29 PM

**Question 7.** **Asked on :**18 November 2022:01:21:25 PM

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(a+b)^{2}= (a+b)(a+b)

= a(a+b) + b(a+b)

= a^{2 }+ ab + ba + b^{2}

^{ }= a^{2 }+ 2ab + b_{2}

*-Answered by Shruti Srivastva * On 05 August 2020:05:43:50 PM

**Question 8.** **Asked on :**18 November 2022:01:20:44 PM

*-Added by Shruti Srivastva * See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

(a+b)

*-Answered by Shruti Srivastva * On 05 August 2020:05:42:16 PM

**Question 9.** **Asked on :**18 November 2022:01:16:49 PM

Simplify combining like terms

(1) 21b - 32 +7b - 20b*-Added by Master Purushottam* See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

21b - 32 + 7b - 20b

=(21b+7b -20b) - 32

=8b - 32 Answer

*-Answered by Nishant Verma* On 17 October 2019:02:37:18 PM

**Answer:**

21b - 32 + 7b - 20b

=(21b+7b -20b) - 32

=8b - 32 Answer

*-Answered by Shivang Gupta* On 25 August 2019:03:19:08 PM

**Answer:**

21b - 32 + 7b - 20b

=(21b+7b -20b) - 32

=8b - 32 Answer

*-Answered by Master Purushottam* On 22 August 2019:09:00:32 PM

**Answer:**

21b - 32 + 7b - 20b

=(21b+7b -20b) - 32

=8b - 32 Answer

*-Answered by Akki Chauhan* On 10 January 2019:10:54:03 AM

**Answer:**

21b - 32 + 7b - 20b

=(21b+7b -20b) - 32

=8b - 32 Answer

*-Answered by Himanshi Verma* On 07 January 2019:11:57:04 PM

**Answer:**

21b - 32 + 7b - 20b

= 21b + 7b - 20b - 32

= 28b - 20b - 32

= 8b - 32 **Answer**

*-Answered by ATP Admin* On 07 January 2019:05:03:13 PM

**Question 10.** **Asked on :**18 November 2022:01:19:03 PM

Find the sum : 3p^{2}q^{2} - 4pq + 5, - 10p^{2}q^{2}, 15 + 9pq + 7p^{2}q^{2}

*-Added by Master Purushottam* See More Answers **Mathematics** » **Algebraic Expressions**

**Answer:**

3p^{2}q^{2} - 4pq + 5 + (-10p^{2}q^{2}) + 15 + 9pq + 7p^{2}q^{2}

= 3p^{2}q^{2} + 7p^{2}q^{2} - 10p^{2}q^{2} + 9pq - 4pq + 5 + 15

= 10p^{2}q^{2} - 10p^{2}q^{2} + 5pq + 20

= 5pq + 20

*-Answered by Nishant Verma* On 17 October 2019:02:37:38 PM

**Answer:**

3p^{2}q^{2} - 4pq + 5 + (-10p^{2}q^{2}) + 15 + 9pq + 7p^{2}q^{2}

= 3p^{2}q^{2} + 7p^{2}q^{2} - 10p^{2}q^{2} + 9pq - 4pq + 5 + 15

= 10p^{2}q^{2} - 10p^{2}q^{2} + 5pq + 20

= 5pq + 20

*-Answered by Master Purushottam* On 22 August 2019:09:00:43 PM

**Answer:**

3p^{2}q^{2} - 4pq + 5 + (-10p^{2}q^{2}) + 15 + 9pq + 7p^{2}q^{2}

= 3p^{2}q^{2} + 7p^{2}q^{2} - 10p^{2}q^{2} + 9pq - 4pq + 5 + 15

= 10p^{2}q^{2} - 10p^{2}q^{2} + 5pq + 20

= 5pq + 20 **Answer**

*-Answered by Akki Chauhan* On 10 January 2019:10:54:27 AM

**Answer:**

3p^{2}q^{2} - 4pq + 5 + (-10p^{2}q^{2}) + 15 + 9pq + 7p^{2}q^{2}

= 3p^{2}q^{2} + 7p^{2}q^{2} - 10p^{2}q^{2} + 9pq - 4pq + 5 + 15

= 10p^{2}q^{2} - 10p^{2}q^{2} + 5pq + 20

= 5pq + 20 **Answer**

*-Answered by Himanshi Verma* On 07 January 2019:11:41:18 PM

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