Fewpal
0 votes
11 views
in Mathematics by (49.4k points)
closed by

Use a formula to multiply: 

i. (x – 5)(x + 5) 

ii. (2a – 13)(2a + 13) 

iii. (4z – 5y)(4z + 5y) 

iv. (2t – 5)(2t + 5)

1 Answer

+1 vote
by (48.8k points)
selected by
 
Best answer

i. Here, a = x and b = 5 

(x – 5)(x + 5) = (x)2 – (5)2 …. [(a + b)(a – b) = a2 – b2 ] 

= x2 – 25 

ii. Here, A = 2a and B = 13 

(2a – 13)(2a + 13) = (2a)2 – (13)2 …. [(A + B)(A – B) = A2 – B2 ] 

= 4a2 – 169 

iii. Here, a = 4z and b = 5y 

(4z – 5y)(4z + 5y) = (4z)2 – (5y)2 …. [(a + b)(a – b) = a2 – b2 ] 

= 16z2 – 25y2 

iv. Here, a = 2t and b = 5 

(2t – 5)(2t + 5) = (2t)2 – (5)2 …. [(a + b)(a – b) = a2  – b2 ] 

= 4t2  – 25

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

...