NCTB Class 7 Math Chapter Five Exercise 5.2 Solution

NCTB Class 7 Math Chapter Five Exercise 5.2 Solution by Math Expert. Bangladesh Board Class 7 Math Solution Chapter 5.2 “Algebraic Formulaic and Applications” Exercise 5.2 Solution.

Board

NCTB
Class

7

Subject

Math
Chapter

5

Chapter Name

“Algebraic Formulaic and Applications”
Exercise

5.2 Solution

Exercise:- 5.2

(1) Solution:- (4x+3) (4x-3)

= (4x)2 – (3)2

= 16x2 -9

(2) Solution:- (13-12p) (13+12p)

= (13)2 – (12p)2

= 169 – 144p2

(3) Solution:- (ab+3) (ab-3)

= (a b)2 – (3)2

= a2 b2 – 9

(4) Solution:- (10-xy) (10+xy)

= (10)2 – (x y)2

= 100 – x2y2

(5) Solution:- (4x2+3y2) (4x2-3y2)

= (4x2)2 – (3y2)2

= 16x4– 9y4

(6) Solution:- (a-b-c) (a+ b+ c)

= a- (b +c)}{a+ (b +c)}

= {a +(b +c)} {a- (b +c)}

= a2- (b +c)2

= a2– (b2+2bc+c2)

= a2-b2 -2bc-c2

(8) Solution:- (x-1/2a) (x-5/2a)

= x2+ (-1/2a – 5/2a) x + (-1/2 a) (-5/2a)

= x2+ (-a-5a/2)x + 5a2/4

= x2+ (-6a/2)x + 4a2+4

= x2- 3ax + 5/4a2

(9) Solution:- (1/4x – 1/3y) (1/4x + 1/3y)

= (1/4x)2 – (1/3y)2

= x2/16 – y2/9

(10) Solution:- (a4+3a2 x2+ 9x4) (9x4– 3a2 x2 + a4)

= {(a4+9x4) + 3a2 x2} {a4+ 9x4) – 3a2 x2}

= (a4+9x4)2 – (3a2n2)2

= (a4)2+ 2x2a4x9x4+ (9x4)2 – 9a4x4

= a8+ 18a4 x4 + 81x8– 9 a4 x 44

(11) Solution:- (x+1) (x-1) (x2+1)

= (x2-1) (x2+1)

= (x2)2 – (1)2

= x4-1

(12) Solution:- (9a2+b2) (3a+b) (3a-b)

= (9a2+b2) (9a2 – b2)

= (9a2)2 – (b2) 2

= 81a4 – b4

Updated: December 16, 2020 — 10:42 am

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